diff --git a/dom/base/Document.cpp b/dom/base/Document.cpp
index 2078e286b316..7a998c8a35cd 100644
--- a/dom/base/Document.cpp
+++ b/dom/base/Document.cpp
@@ -12394,7 +12394,8 @@ already_AddRefed<nsIURI> Document::ResolvePreloadImage(
 
 void Document::PreLoadImage(nsIURI* aUri, const nsAString& aCrossOriginAttr,
                             ReferrerPolicyEnum aReferrerPolicy, bool aIsImgSet,
-                            bool aLinkPreload, uint64_t aEarlyHintPreloaderId) {
+                            bool aLinkPreload, uint64_t aEarlyHintPreloaderId,
+                            const nsAString& aFetchPriority) {
   nsLoadFlags loadFlags = nsIRequest::LOAD_NORMAL |
                           nsContentUtils::CORSModeToLoadImageFlags(
                               Element::StringToCORSMode(aCrossOriginAttr));
@@ -12415,7 +12416,8 @@ void Document::PreLoadImage(nsIURI* aUri, const nsAString& aCrossOriginAttr,
   nsresult rv = nsContentUtils::LoadImage(
       aUri, static_cast<nsINode*>(this), this, NodePrincipal(), 0, referrerInfo,
       nullptr /* no observer */, loadFlags, initiator, getter_AddRefs(request),
-      policyType, false /* urgent */, aLinkPreload, aEarlyHintPreloaderId);
+      policyType, false /* urgent */, aLinkPreload, aEarlyHintPreloaderId,
+      nsGenericHTMLElement::ToFetchPriority(aFetchPriority));
 
   // Pin image-reference to avoid evicting it from the img-cache before
   // the "real" load occurs. Unpinned in DispatchContentLoadedEvents and
@@ -12428,7 +12430,8 @@ void Document::PreLoadImage(nsIURI* aUri, const nsAString& aCrossOriginAttr,
 void Document::MaybePreLoadImage(nsIURI* aUri,
                                  const nsAString& aCrossOriginAttr,
                                  ReferrerPolicyEnum aReferrerPolicy,
-                                 bool aIsImgSet, bool aLinkPreload) {
+                                 bool aIsImgSet, bool aLinkPreload,
+                                 const nsAString& aFetchPriority) {
   const CORSMode corsMode = dom::Element::StringToCORSMode(aCrossOriginAttr);
   if (aLinkPreload) {
     // Check if the image was already preloaded in this document to avoid
@@ -12437,7 +12440,7 @@ void Document::MaybePreLoadImage(nsIURI* aUri,
         PreloadHashKey::CreateAsImage(aUri, NodePrincipal(), corsMode);
     if (!mPreloadService.PreloadExists(key)) {
       PreLoadImage(aUri, aCrossOriginAttr, aReferrerPolicy, aIsImgSet,
-                   aLinkPreload, 0);
+                   aLinkPreload, 0, aFetchPriority);
     }
     return;
   }
@@ -12451,7 +12454,7 @@ void Document::MaybePreLoadImage(nsIURI* aUri,
 
   // Image not in cache - trigger preload
   PreLoadImage(aUri, aCrossOriginAttr, aReferrerPolicy, aIsImgSet, aLinkPreload,
-               0);
+               0, aFetchPriority);
 }
 
 void Document::MaybePreconnect(nsIURI* aOrigURI, mozilla::CORSMode aCORSMode) {
diff --git a/dom/base/Document.h b/dom/base/Document.h
index 6a2bd55a9caa..75cffe66be3d 100644
--- a/dom/base/Document.h
+++ b/dom/base/Document.h
@@ -2930,10 +2930,11 @@ class Document : public nsINode,
    */
   void MaybePreLoadImage(nsIURI* uri, const nsAString& aCrossOriginAttr,
                          ReferrerPolicyEnum aReferrerPolicy, bool aIsImgSet,
-                         bool aLinkPreload);
+                         bool aLinkPreload, const nsAString& aFetchPriority);
   void PreLoadImage(nsIURI* uri, const nsAString& aCrossOriginAttr,
                     ReferrerPolicyEnum aReferrerPolicy, bool aIsImgSet,
-                    bool aLinkPreload, uint64_t aEarlyHintPreloaderId);
+                    bool aLinkPreload, uint64_t aEarlyHintPreloaderId,
+                    const nsAString& aFetchPriority);
 
   /**
    * Called by images to forget an image preload when they start doing
diff --git a/dom/base/nsContentUtils.cpp b/dom/base/nsContentUtils.cpp
index d849b1392780..b668e3f86b00 100644
--- a/dom/base/nsContentUtils.cpp
+++ b/dom/base/nsContentUtils.cpp
@@ -4004,7 +4004,8 @@ nsresult nsContentUtils::LoadImage(
     int32_t aLoadFlags, const nsAString& initiatorType,
     imgRequestProxy** aRequest, nsContentPolicyType aContentPolicyType,
     bool aUseUrgentStartForChannel, bool aLinkPreload,
-    uint64_t aEarlyHintPreloaderId) {
+    uint64_t aEarlyHintPreloaderId,
+    mozilla::dom::FetchPriority aFetchPriority) {
   MOZ_ASSERT(aURI, "Must have a URI");
   MOZ_ASSERT(aContext, "Must have a context");
   MOZ_ASSERT(aLoadingDocument, "Must have a document");
@@ -4041,7 +4042,7 @@ nsresult nsContentUtils::LoadImage(
                               initiatorType,      /* the load initiator */
                               aUseUrgentStartForChannel, /* urgent-start flag */
                               aLinkPreload, /* <link preload> initiator */
-                              aEarlyHintPreloaderId, aRequest);
+                              aEarlyHintPreloaderId, aFetchPriority, aRequest);
 }
 
 // static
diff --git a/dom/base/nsContentUtils.h b/dom/base/nsContentUtils.h
index 95744fe8315b..38736f979ba2 100644
--- a/dom/base/nsContentUtils.h
+++ b/dom/base/nsContentUtils.h
@@ -39,6 +39,7 @@
 #include "mozilla/UniquePtr.h"
 #include "mozilla/dom/BindingDeclarations.h"
 #include "mozilla/dom/FromParser.h"
+#include "mozilla/dom/FetchPriority.h"
 #include "mozilla/fallible.h"
 #include "mozilla/gfx/Point.h"
 #include "nsCOMPtr.h"
@@ -1026,7 +1027,9 @@ class nsContentUtils {
       nsContentPolicyType aContentPolicyType =
           nsIContentPolicy::TYPE_INTERNAL_IMAGE,
       bool aUseUrgentStartForChannel = false, bool aLinkPreload = false,
-      uint64_t aEarlyHintPreloaderId = 0);
+      uint64_t aEarlyHintPreloaderId = 0,
+      mozilla::dom::FetchPriority aFetchPriority =
+          mozilla::dom::FetchPriority::Auto);
 
   /**
    * Obtain an image loader that respects the given document/channel's privacy
diff --git a/image/imgLoader.cpp b/image/imgLoader.cpp
index 737d99ff1512..eeb90cf374ac 100644
--- a/image/imgLoader.cpp
+++ b/image/imgLoader.cpp
@@ -32,6 +32,7 @@
 #include "mozilla/StaticPrefs_network.h"
 #include "mozilla/StoragePrincipalHelper.h"
 #include "mozilla/dom/ContentParent.h"
+#include "mozilla/dom/FetchPriority.h"
 #include "mozilla/dom/nsMixedContentBlocker.h"
 #include "mozilla/image/ImageMemoryReporter.h"
 #include "mozilla/layers/CompositorManagerChild.h"
@@ -815,6 +816,28 @@ static bool ValidateSecurityInfo(imgRequest* aRequest,
                                /* aSendCSPViolationReports */ false);
 }
 
+static void AdjustPriorityForImages(nsIChannel* aChannel,
+                                    nsLoadFlags aLoadFlags,
+                                    FetchPriority aFetchPriority) {
+  // Image channels are loaded by default with reduced priority.
+  if (nsCOMPtr<nsISupportsPriority> supportsPriority =
+          do_QueryInterface(aChannel)) {
+    int32_t priority = nsISupportsPriority::PRIORITY_LOW;
+
+    // Adjust priority according to fetchpriorty attribute.
+    if (StaticPrefs::network_fetchpriority_enabled()) {
+      priority += FETCH_PRIORITY_ADJUSTMENT_FOR(images, aFetchPriority);
+    }
+
+    // Further reduce priority for background loads
+    if (aLoadFlags & nsIRequest::LOAD_BACKGROUND) {
+      ++priority;
+    }
+
+    supportsPriority->AdjustPriority(priority);
+  }
+}
+
 static nsresult NewImageChannel(
     nsIChannel** aResult,
     // If aForcePrincipalCheckForCacheEntry is true, then we will
@@ -828,7 +851,8 @@ static nsresult NewImageChannel(
     nsIReferrerInfo* aReferrerInfo, nsILoadGroup* aLoadGroup,
     nsLoadFlags aLoadFlags, nsContentPolicyType aPolicyType,
     nsIPrincipal* aTriggeringPrincipal, nsINode* aRequestingNode,
-    bool aRespectPrivacy, uint64_t aEarlyHintPreloaderId) {
+    bool aRespectPrivacy, uint64_t aEarlyHintPreloaderId,
+    FetchPriority aFetchPriority) {
   MOZ_ASSERT(aResult);
 
   nsresult rv;
@@ -948,17 +972,7 @@ static nsresult NewImageChannel(
     }
   }
 
-  // Image channels are loaded by default with reduced priority.
-  nsCOMPtr<nsISupportsPriority> p = do_QueryInterface(*aResult);
-  if (p) {
-    uint32_t priority = nsISupportsPriority::PRIORITY_LOW;
-
-    if (aLoadFlags & nsIRequest::LOAD_BACKGROUND) {
-      ++priority;  // further reduce priority for background loads
-    }
-
-    p->AdjustPriority(priority);
-  }
+  AdjustPriorityForImages(*aResult, aLoadFlags, aFetchPriority);
 
   // Create a new loadgroup for this new channel, using the old group as
   // the parent. The indirection keeps the channel insulated from cancels,
@@ -1715,7 +1729,8 @@ bool imgLoader::ValidateRequestWithNewChannel(
     uint64_t aInnerWindowId, nsLoadFlags aLoadFlags,
     nsContentPolicyType aLoadPolicyType, imgRequestProxy** aProxyRequest,
     nsIPrincipal* aTriggeringPrincipal, CORSMode aCORSMode, bool aLinkPreload,
-    uint64_t aEarlyHintPreloaderId, bool* aNewChannelCreated) {
+    uint64_t aEarlyHintPreloaderId, FetchPriority aFetchPriority,
+    bool* aNewChannelCreated) {
   // now we need to insert a new channel request object in between the real
   // request and the proxy that basically delays loading the image until it
   // gets a 304 or figures out that this needs to be a new request
@@ -1758,11 +1773,11 @@ bool imgLoader::ValidateRequestWithNewChannel(
   // cache.
   nsCOMPtr<nsIChannel> newChannel;
   bool forcePrincipalCheck;
-  rv =
-      NewImageChannel(getter_AddRefs(newChannel), &forcePrincipalCheck, aURI,
-                      aInitialDocumentURI, aCORSMode, aReferrerInfo, aLoadGroup,
-                      aLoadFlags, aLoadPolicyType, aTriggeringPrincipal,
-                      aLoadingDocument, mRespectPrivacy, aEarlyHintPreloaderId);
+  rv = NewImageChannel(getter_AddRefs(newChannel), &forcePrincipalCheck, aURI,
+                       aInitialDocumentURI, aCORSMode, aReferrerInfo,
+                       aLoadGroup, aLoadFlags, aLoadPolicyType,
+                       aTriggeringPrincipal, aLoadingDocument, mRespectPrivacy,
+                       aEarlyHintPreloaderId, aFetchPriority);
   if (NS_FAILED(rv)) {
     return false;
   }
@@ -1841,7 +1856,7 @@ void imgLoader::NotifyObserversForCachedImage(
     imgCacheEntry* aEntry, imgRequest* request, nsIURI* aURI,
     nsIReferrerInfo* aReferrerInfo, Document* aLoadingDocument,
     nsIPrincipal* aTriggeringPrincipal, CORSMode aCORSMode,
-    uint64_t aEarlyHintPreloaderId) {
+    uint64_t aEarlyHintPreloaderId, FetchPriority aFetchPriority) {
   if (aEntry->HasNotified()) {
     return;
   }
@@ -1860,7 +1875,7 @@ void imgLoader::NotifyObserversForCachedImage(
       getter_AddRefs(newChannel), &forcePrincipalCheck, aURI, nullptr,
       aCORSMode, aReferrerInfo, nullptr, 0,
       nsIContentPolicy::TYPE_INTERNAL_IMAGE, aTriggeringPrincipal,
-      aLoadingDocument, mRespectPrivacy, aEarlyHintPreloaderId);
+      aLoadingDocument, mRespectPrivacy, aEarlyHintPreloaderId, aFetchPriority);
   if (NS_FAILED(rv)) {
     return;
   }
@@ -1885,7 +1900,8 @@ bool imgLoader::ValidateEntry(
     nsLoadFlags aLoadFlags, nsContentPolicyType aLoadPolicyType,
     bool aCanMakeNewChannel, bool* aNewChannelCreated,
     imgRequestProxy** aProxyRequest, nsIPrincipal* aTriggeringPrincipal,
-    CORSMode aCORSMode, bool aLinkPreload, uint64_t aEarlyHintPreloaderId) {
+    CORSMode aCORSMode, bool aLinkPreload, uint64_t aEarlyHintPreloaderId,
+    FetchPriority aFetchPriority) {
   LOG_SCOPE(gImgLog, "imgLoader::ValidateEntry");
 
   // If the expiration time is zero, then the request has not gotten far enough
@@ -2013,13 +2029,13 @@ bool imgLoader::ValidateEntry(
         request, aURI, aInitialDocumentURI, aReferrerInfo, aLoadGroup,
         aObserver, aLoadingDocument, innerWindowID, aLoadFlags, aLoadPolicyType,
         aProxyRequest, aTriggeringPrincipal, aCORSMode, aLinkPreload,
-        aEarlyHintPreloaderId, aNewChannelCreated);
+        aEarlyHintPreloaderId, aFetchPriority, aNewChannelCreated);
   }
 
   if (!validateRequest) {
-    NotifyObserversForCachedImage(aEntry, request, aURI, aReferrerInfo,
-                                  aLoadingDocument, aTriggeringPrincipal,
-                                  aCORSMode, aEarlyHintPreloaderId);
+    NotifyObserversForCachedImage(
+        aEntry, request, aURI, aReferrerInfo, aLoadingDocument,
+        aTriggeringPrincipal, aCORSMode, aEarlyHintPreloaderId, aFetchPriority);
   }
 
   return !validateRequest;
@@ -2174,7 +2190,7 @@ imgLoader::LoadImageXPCOM(
                 0, aLoadGroup, aObserver, aLoadingDocument, aLoadingDocument,
                 aLoadFlags, aCacheKey, aContentPolicyType, u""_ns,
                 /* aUseUrgentStartForChannel */ false, /* aListPreload */ false,
-                0, &proxy);
+                0, FetchPriority::Auto, &proxy);
   *_retval = proxy;
   return rv;
 }
@@ -2233,7 +2249,7 @@ nsresult imgLoader::LoadImage(
     nsISupports* aCacheKey, nsContentPolicyType aContentPolicyType,
     const nsAString& initiatorType, bool aUseUrgentStartForChannel,
     bool aLinkPreload, uint64_t aEarlyHintPreloaderId,
-    imgRequestProxy** _retval) {
+    FetchPriority aFetchPriority, imgRequestProxy** _retval) {
   VerifyCacheSizes();
 
   NS_ASSERTION(aURI, "imgLoader::LoadImage -- NULL URI pointer");
@@ -2386,7 +2402,7 @@ nsresult imgLoader::LoadImage(
                       aLoadGroup, aObserver, aLoadingDocument, requestFlags,
                       aContentPolicyType, true, &newChannelCreated, _retval,
                       aTriggeringPrincipal, corsmode, aLinkPreload,
-                      aEarlyHintPreloaderId)) {
+                      aEarlyHintPreloaderId, aFetchPriority)) {
       request = entry->GetRequest();
 
       // If this entry has no proxies, its request has no reference to the
@@ -2436,7 +2452,7 @@ nsresult imgLoader::LoadImage(
                          aInitialDocumentURI, corsmode, aReferrerInfo,
                          aLoadGroup, requestFlags, aContentPolicyType,
                          aTriggeringPrincipal, aContext, mRespectPrivacy,
-                         aEarlyHintPreloaderId);
+                         aEarlyHintPreloaderId, aFetchPriority);
     if (NS_FAILED(rv)) {
       return NS_ERROR_FAILURE;
     }
@@ -2650,7 +2666,8 @@ nsresult imgLoader::LoadImageWithChannel(nsIChannel* channel,
 
       if (ValidateEntry(entry, uri, nullptr, nullptr, nullptr, aObserver,
                         aLoadingDocument, requestFlags, policyType, false,
-                        nullptr, nullptr, nullptr, corsMode, false, 0)) {
+                        nullptr, nullptr, nullptr, corsMode, false, 0,
+                        FetchPriority::Auto)) {
         request = entry->GetRequest();
       } else {
         nsCOMPtr<nsICacheInfoChannel> cacheChan(do_QueryInterface(channel));
diff --git a/image/imgLoader.h b/image/imgLoader.h
index c5155067903d..742351792533 100644
--- a/image/imgLoader.h
+++ b/image/imgLoader.h
@@ -37,6 +37,7 @@ class imgMemoryReporter;
 namespace mozilla {
 namespace dom {
 class Document;
+enum class FetchPriority : uint8_t;
 }
 }  // namespace mozilla
 
@@ -238,7 +239,8 @@ class imgLoader final : public imgILoader,
       nsLoadFlags aLoadFlags, nsISupports* aCacheKey,
       nsContentPolicyType aContentPolicyType, const nsAString& initiatorType,
       bool aUseUrgentStartForChannel, bool aLinkPreload,
-      uint64_t aEarlyHintPreloaderId, imgRequestProxy** _retval);
+      uint64_t aEarlyHintPreloaderId,
+      mozilla::dom::FetchPriority aFetchPriority, imgRequestProxy** _retval);
 
   [[nodiscard]] nsresult LoadImageWithChannel(
       nsIChannel* channel, imgINotificationObserver* aObserver,
@@ -349,7 +351,8 @@ class imgLoader final : public imgILoader,
                      bool aCanMakeNewChannel, bool* aNewChannelCreated,
                      imgRequestProxy** aProxyRequest,
                      nsIPrincipal* aTriggeringPrincipal, mozilla::CORSMode,
-                     bool aLinkPreload, uint64_t aEarlyHintPreloaderId);
+                     bool aLinkPreload, uint64_t aEarlyHintPreloaderId,
+                     mozilla::dom::FetchPriority aFetchPriority);
 
   bool ValidateRequestWithNewChannel(
       imgRequest* request, nsIURI* aURI, nsIURI* aInitialDocumentURI,
@@ -359,15 +362,14 @@ class imgLoader final : public imgILoader,
       nsLoadFlags aLoadFlags, nsContentPolicyType aContentPolicyType,
       imgRequestProxy** aProxyRequest, nsIPrincipal* aLoadingPrincipal,
       mozilla::CORSMode, bool aLinkPreload, uint64_t aEarlyHintPreloaderId,
-      bool* aNewChannelCreated);
+      mozilla::dom::FetchPriority aFetchPriority, bool* aNewChannelCreated);
 
-  void NotifyObserversForCachedImage(imgCacheEntry* aEntry, imgRequest* request,
-                                     nsIURI* aURI,
-                                     nsIReferrerInfo* aReferrerInfo,
-                                     mozilla::dom::Document* aLoadingDocument,
-                                     nsIPrincipal* aLoadingPrincipal,
-                                     mozilla::CORSMode,
-                                     uint64_t aEarlyHintPreloaderId);
+  void NotifyObserversForCachedImage(
+      imgCacheEntry* aEntry, imgRequest* request, nsIURI* aURI,
+      nsIReferrerInfo* aReferrerInfo, mozilla::dom::Document* aLoadingDocument,
+      nsIPrincipal* aTriggeringPrincipal, mozilla::CORSMode,
+      uint64_t aEarlyHintPreloaderId,
+      mozilla::dom::FetchPriority aFetchPriority);
   // aURI may be different from imgRequest's URI in the case of blob URIs, as we
   // can share requests with different URIs.
   nsresult CreateNewProxyForRequest(imgRequest* aRequest, nsIURI* aURI,
diff --git a/layout/generic/nsImageFrame.cpp b/layout/generic/nsImageFrame.cpp
index e0a6243ed2ad..ddeff68f23b4 100644
--- a/layout/generic/nsImageFrame.cpp
+++ b/layout/generic/nsImageFrame.cpp
@@ -18,6 +18,7 @@
 #include "mozilla/DebugOnly.h"
 #include "mozilla/Encoding.h"
 #include "mozilla/HTMLEditor.h"
+#include "mozilla/dom/FetchPriority.h"
 #include "mozilla/dom/ImageTracker.h"
 #include "mozilla/gfx/2D.h"
 #include "mozilla/gfx/Helpers.h"
@@ -268,7 +269,7 @@ BrokenImageIcon::BrokenImageIcon(const nsImageFrame& aFrame) {
                     loadFlags, nullptr, contentPolicyType, u""_ns,
                     false, /* aUseUrgentStartForChannel */
                     false, /* aLinkPreload */
-                    0, getter_AddRefs(mImage));
+                    0, FetchPriority::Auto, getter_AddRefs(mImage));
   Unused << NS_WARN_IF(NS_FAILED(rv));
 }
 
diff --git a/modules/libpref/init/StaticPrefList.yaml b/modules/libpref/init/StaticPrefList.yaml
index 4e54ae1d3c53..23d03397d58b 100644
--- a/modules/libpref/init/StaticPrefList.yaml
+++ b/modules/libpref/init/StaticPrefList.yaml
@@ -11993,6 +11993,26 @@
   value: 0
   mirror: always
 
+# Adjustments to apply to the internal priority of <link rel=preload as=images
+# fetchpriority=low/high/auto> and <img fetchpriority=low/high/auto> with
+# respect to the case when network.fetchpriority is disabled.
+# - When the flag is disabled, Gecko currently sets priority to LOW.
+# - When the flag is enabled, it respectively maps to LOW/LOW/HIGH.
+# The image code can currently further adjust the priority for image load, see
+# imgRequest::BoostPriority and AdjustPriorityForImages.
+- name: network.fetchpriority.adjustments.images.low
+  type: int32_t
+  value: 0
+  mirror: always
+- name: network.fetchpriority.adjustments.images.high
+  type: int32_t
+  value: -20
+  mirror: always
+- name: network.fetchpriority.adjustments.images.auto
+  type: int32_t
+  value: 0
+  mirror: always
+
 # Enables `<link rel="preconnect">` tag and `Link: rel=preconnect` response header
 # handling.
 - name: network.preconnect
diff --git a/parser/html/nsHtml5SpeculativeLoad.cpp b/parser/html/nsHtml5SpeculativeLoad.cpp
index b85c31f655c6..4ddc15b957ab 100644
--- a/parser/html/nsHtml5SpeculativeLoad.cpp
+++ b/parser/html/nsHtml5SpeculativeLoad.cpp
@@ -45,7 +45,7 @@ void nsHtml5SpeculativeLoad::Perform(nsHtml5TreeOpExecutor* aExecutor) {
       aExecutor->PreloadImage(
           mUrlOrSizes, mCrossOrigin, mMedia, mCharsetOrSrcset,
           mTypeOrCharsetSourceOrDocumentModeOrMetaCSPOrSizesOrIntegrity,
-          mReferrerPolicyOrIntegrity, mIsLinkPreload);
+          mReferrerPolicyOrIntegrity, mIsLinkPreload, mFetchPriority);
       break;
     case eSpeculativeLoadOpenPicture:
       aExecutor->PreloadOpenPicture();
diff --git a/parser/html/nsHtml5SpeculativeLoad.h b/parser/html/nsHtml5SpeculativeLoad.h
index d53d3a5b46cc..61ec92e6a4e9 100644
--- a/parser/html/nsHtml5SpeculativeLoad.h
+++ b/parser/html/nsHtml5SpeculativeLoad.h
@@ -75,7 +75,7 @@ class nsHtml5SpeculativeLoad {
   inline void InitImage(nsHtml5String aUrl, nsHtml5String aCrossOrigin,
                         nsHtml5String aMedia, nsHtml5String aReferrerPolicy,
                         nsHtml5String aSrcset, nsHtml5String aSizes,
-                        bool aLinkPreload) {
+                        bool aLinkPreload, nsHtml5String aFetchPriority) {
     MOZ_ASSERT(mOpCode == eSpeculativeLoadUninitialized,
                "Trying to reinitialize a speculative load!");
     mOpCode = eSpeculativeLoadImage;
@@ -92,6 +92,7 @@ class nsHtml5SpeculativeLoad {
     aSizes.ToString(
         mTypeOrCharsetSourceOrDocumentModeOrMetaCSPOrSizesOrIntegrity);
     mIsLinkPreload = aLinkPreload;
+    aFetchPriority.ToString(mFetchPriority);
   }
 
   inline void InitFont(nsHtml5String aUrl, nsHtml5String aCrossOrigin,
diff --git a/parser/html/nsHtml5TreeBuilderCppSupplement.h b/parser/html/nsHtml5TreeBuilderCppSupplement.h
index f39f456663d1..2eb7fa91ee52 100644
--- a/parser/html/nsHtml5TreeBuilderCppSupplement.h
+++ b/parser/html/nsHtml5TreeBuilderCppSupplement.h
@@ -215,9 +215,16 @@ nsIContentHandle* nsHtml5TreeBuilder::createElement(
                 nsHtml5AttributeName::ATTR_REFERRERPOLICY);
             nsHtml5String sizes =
                 aAttributes->getValue(nsHtml5AttributeName::ATTR_SIZES);
+
+            // TODO: support the fetchpriority attribute in bug 1839313.
+            //       Meanwhile the empty string is used since it's mapped to the
+            //       auto state
+            //       (https://html.spec.whatwg.org/#fetch-priority-attribute).
+            auto fetchPriority = nsHtml5String::EmptyString();
+
             mSpeculativeLoadQueue.AppendElement()->InitImage(
                 url, crossOrigin, /* aMedia = */ nullptr, referrerPolicy,
-                srcset, sizes, false);
+                srcset, sizes, false, fetchPriority);
           }
         } else if (nsGkAtoms::source == aName) {
           nsHtml5String srcset =
@@ -435,7 +442,7 @@ nsIContentHandle* nsHtml5TreeBuilder::createElement(
                       nsHtml5AttributeName::ATTR_IMAGESIZES);
                   mSpeculativeLoadQueue.AppendElement()->InitImage(
                       url, crossOrigin, media, referrerPolicy, srcset, sizes,
-                      true);
+                      true, fetchPriority);
                 } else if (as.LowerCaseEqualsASCII("font")) {
                   mSpeculativeLoadQueue.AppendElement()->InitFont(
                       url, crossOrigin, media, referrerPolicy, fetchPriority);
@@ -487,8 +494,14 @@ nsIContentHandle* nsHtml5TreeBuilder::createElement(
           nsHtml5String url =
               aAttributes->getValue(nsHtml5AttributeName::ATTR_POSTER);
           if (url) {
+            // Fetch priority is not supported for video. Nullptr will map to
+            // the auto state
+            // (https://html.spec.whatwg.org/#fetch-priority-attribute).
+            auto fetchPriority = nullptr;
+
             mSpeculativeLoadQueue.AppendElement()->InitImage(
-                url, nullptr, nullptr, nullptr, nullptr, nullptr, false);
+                url, nullptr, nullptr, nullptr, nullptr, nullptr, false,
+                fetchPriority);
           }
         } else if (nsGkAtoms::style == aName) {
           mImportScanner.Start();
@@ -543,8 +556,15 @@ nsIContentHandle* nsHtml5TreeBuilder::createElement(
             url = aAttributes->getValue(nsHtml5AttributeName::ATTR_XLINK_HREF);
           }
           if (url) {
+            // Currently SVG's `<image>` element lacks support for
+            // `fetchpriority`, see bug 1847712. Hence passing nullptr which
+            // maps to the auto state
+            // (https://html.spec.whatwg.org/#fetch-priority-attribute).
+            auto fetchPriority = nullptr;
+
             mSpeculativeLoadQueue.AppendElement()->InitImage(
-                url, nullptr, nullptr, nullptr, nullptr, nullptr, false);
+                url, nullptr, nullptr, nullptr, nullptr, nullptr, false,
+                fetchPriority);
           }
         } else if (nsGkAtoms::script == aName) {
           nsHtml5TreeOperation* treeOp =
diff --git a/parser/html/nsHtml5TreeOpExecutor.cpp b/parser/html/nsHtml5TreeOpExecutor.cpp
index 3cb38dcf28a5..f2c47c42a6b6 100644
--- a/parser/html/nsHtml5TreeOpExecutor.cpp
+++ b/parser/html/nsHtml5TreeOpExecutor.cpp
@@ -1261,7 +1261,8 @@ void nsHtml5TreeOpExecutor::PreloadStyle(
 void nsHtml5TreeOpExecutor::PreloadImage(
     const nsAString& aURL, const nsAString& aCrossOrigin,
     const nsAString& aMedia, const nsAString& aSrcset, const nsAString& aSizes,
-    const nsAString& aImageReferrerPolicy, bool aLinkPreload) {
+    const nsAString& aImageReferrerPolicy, bool aLinkPreload,
+    const nsAString& aFetchPriority) {
   nsCOMPtr<nsIURI> baseURI = BaseURIForPreload();
   bool isImgSet = false;
   nsCOMPtr<nsIURI> uri =
@@ -1270,7 +1271,7 @@ void nsHtml5TreeOpExecutor::PreloadImage(
     // use document wide referrer policy
     mDocument->MaybePreLoadImage(uri, aCrossOrigin,
                                  GetPreloadReferrerPolicy(aImageReferrerPolicy),
-                                 isImgSet, aLinkPreload);
+                                 isImgSet, aLinkPreload, aFetchPriority);
   }
 }
 
diff --git a/parser/html/nsHtml5TreeOpExecutor.h b/parser/html/nsHtml5TreeOpExecutor.h
index 3a8225614770..169fa5a703a6 100644
--- a/parser/html/nsHtml5TreeOpExecutor.h
+++ b/parser/html/nsHtml5TreeOpExecutor.h
@@ -260,7 +260,8 @@ class nsHtml5TreeOpExecutor final
   void PreloadImage(const nsAString& aURL, const nsAString& aCrossOrigin,
                     const nsAString& aMedia, const nsAString& aSrcset,
                     const nsAString& aSizes,
-                    const nsAString& aImageReferrerPolicy, bool aLinkPreload);
+                    const nsAString& aImageReferrerPolicy, bool aLinkPreload,
+                    const nsAString& aFetchPriority);
 
   void PreloadOpenPicture();
 
diff --git a/testing/web-platform/mozilla/meta/fetch/fetchpriority/fetchpriority.h2.html.ini b/testing/web-platform/mozilla/meta/fetch/fetchpriority/fetchpriority.h2.html.ini
index d2ed4028dee8..e87dcd4c44e0 100644
--- a/testing/web-platform/mozilla/meta/fetch/fetchpriority/fetchpriority.h2.html.ini
+++ b/testing/web-platform/mozilla/meta/fetch/fetchpriority/fetchpriority.h2.html.ini
@@ -1,15 +1,6 @@
 [fetchpriority.h2.html]
   lsan-allowed: [mozilla::net::AddStaticElement, InitializeStaticHeaders, mozilla::net::nvFIFO::nvFIFO, mozilla::net::Http2BaseCompressor::Http2BaseCompressor]  # https://bugzilla.mozilla.org/show_bug.cgi?id=1759310
   prefs: [network.fetchpriority.enabled:true]
-  [link-initial-preload-image.h2.html: test different 'fetchpriority' values]
-    expected: FAIL
-
-  [link-dynamic-preload-image.h2.html: test different 'fetchpriority' values]
-    expected: FAIL
-
-  [link-header.h2.html?pipe=|header(Link,<dummy.image?1>; rel=preload; as=image; fetchpriority=low,True)|header(Link,<dummy.image?2>; rel=preload; as=image; fetchpriority=high,True)|header(Link,<dummy.image?3>; rel=preload; as=image; fetchpriority=auto,True)|header(Link,<dummy.image?4>; rel=preload; as=image,True): test different 'fetchpriority' values]
-    expected: FAIL
-
   [image-dynamic-load.h2.html: test different 'fetchpriority' values]
     expected: FAIL
 
diff --git a/testing/web-platform/mozilla/tests/fetch/fetchpriority/fetchpriority-adjustments.html b/testing/web-platform/mozilla/tests/fetch/fetchpriority/fetchpriority-adjustments.html
index 3027cddf310c..71bfbcc0b587 100644
--- a/testing/web-platform/mozilla/tests/fetch/fetchpriority/fetchpriority-adjustments.html
+++ b/testing/web-platform/mozilla/tests/fetch/fetchpriority/fetchpriority-adjustments.html
@@ -18,6 +18,7 @@
       "link-preload-style": SpecialPowers.Ci.nsISupportsPriority.PRIORITY_HIGHEST,
       "non-deferred-style": SpecialPowers.Ci.nsISupportsPriority.PRIORITY_NORMAL,
       "global-fetch-api": SpecialPowers.Ci.nsISupportsPriority.PRIORITY_NORMAL,
+      "images": SpecialPowers.Ci.nsISupportsPriority.PRIORITY_LOW,
   };
   for (const name in prioritiesWhenFetchpriorityDisabled) {
       let adjustments = {};
diff --git a/testing/web-platform/mozilla/tests/fetch/fetchpriority/support/link-tests-data.js b/testing/web-platform/mozilla/tests/fetch/fetchpriority/support/link-tests-data.js
index d20de07fbabf..1606894e2e1e 100644
--- a/testing/web-platform/mozilla/tests/fetch/fetchpriority/support/link-tests-data.js
+++ b/testing/web-platform/mozilla/tests/fetch/fetchpriority/support/link-tests-data.js
@@ -113,16 +113,16 @@ const kExpectedRequestsOfLinkPreloadFontDisabled = [
 
 const kExpectedRequestsOfLinkPreloadImage = [
     {   fileNameAndSuffix: "dummy.image?1",
-        internalPriority: SpecialPowers.Ci.nsISupportsPriority.PRIORITY_LOW
+        internalPriority: SpecialPowers.Ci.nsISupportsPriority.PRIORITY_LOW + 1
     },
     {   fileNameAndSuffix: "dummy.image?2",
-        internalPriority: SpecialPowers.Ci.nsISupportsPriority.PRIORITY_HIGH
+        internalPriority: SpecialPowers.Ci.nsISupportsPriority.PRIORITY_HIGH + 1
     },
     {   fileNameAndSuffix: "dummy.image?3",
-        internalPriority: SpecialPowers.Ci.nsISupportsPriority.PRIORITY_LOW
+        internalPriority: SpecialPowers.Ci.nsISupportsPriority.PRIORITY_LOW + 1
     },
     {   fileNameAndSuffix: "dummy.image?4",
-        internalPriority: SpecialPowers.Ci.nsISupportsPriority.PRIORITY_LOW
+        internalPriority: SpecialPowers.Ci.nsISupportsPriority.PRIORITY_LOW + 1
     },
 ];
 
diff --git a/uriloader/preload/PreloadService.cpp b/uriloader/preload/PreloadService.cpp
index 845c06ef3392..48cf9a364cee 100644
--- a/uriloader/preload/PreloadService.cpp
+++ b/uriloader/preload/PreloadService.cpp
@@ -226,7 +226,8 @@ PreloadService::PreloadOrCoalesceResult PreloadService::PreloadOrCoalesce(
         break;
     }
   } else if (aAs.LowerCaseEqualsASCII("image")) {
-    PreloadImage(uri, aCORS, aReferrerPolicy, isImgSet, aEarlyHintPreloaderId);
+    PreloadImage(uri, aCORS, aReferrerPolicy, isImgSet, aEarlyHintPreloaderId,
+                 aFetchPriority);
   } else if (aAs.LowerCaseEqualsASCII("font")) {
     PreloadFont(uri, aCORS, aReferrerPolicy, aEarlyHintPreloaderId,
                 aFetchPriority);
@@ -258,10 +259,11 @@ void PreloadService::PreloadScript(
 void PreloadService::PreloadImage(nsIURI* aURI, const nsAString& aCrossOrigin,
                                   const nsAString& aImageReferrerPolicy,
                                   bool aIsImgSet,
-                                  uint64_t aEarlyHintPreloaderId) {
-  mDocument->PreLoadImage(aURI, aCrossOrigin,
-                          PreloadReferrerPolicy(aImageReferrerPolicy),
-                          aIsImgSet, true, aEarlyHintPreloaderId);
+                                  uint64_t aEarlyHintPreloaderId,
+                                  const nsAString& aFetchPriority) {
+  mDocument->PreLoadImage(
+      aURI, aCrossOrigin, PreloadReferrerPolicy(aImageReferrerPolicy),
+      aIsImgSet, true, aEarlyHintPreloaderId, aFetchPriority);
 }
 
 void PreloadService::PreloadFont(nsIURI* aURI, const nsAString& aCrossOrigin,
diff --git a/uriloader/preload/PreloadService.h b/uriloader/preload/PreloadService.h
index 5f6566ea34cc..79f5e7b6d137 100644
--- a/uriloader/preload/PreloadService.h
+++ b/uriloader/preload/PreloadService.h
@@ -90,7 +90,8 @@ class PreloadService {
 
   void PreloadImage(nsIURI* aURI, const nsAString& aCrossOrigin,
                     const nsAString& aImageReferrerPolicy, bool aIsImgSet,
-                    uint64_t aEarlyHintPreloaderId);
+                    uint64_t aEarlyHintPreloaderId,
+                    const nsAString& aFetchPriority);
 
   void PreloadFont(nsIURI* aURI, const nsAString& aCrossOrigin,
                    const nsAString& aReferrerPolicy,
diff --git a/widget/IconLoader.cpp b/widget/IconLoader.cpp
index 5c0488e3e21e..41d2a29bc741 100644
--- a/widget/IconLoader.cpp
+++ b/widget/IconLoader.cpp
@@ -9,6 +9,7 @@
 #include "imgLoader.h"
 #include "imgRequestProxy.h"
 #include "mozilla/dom/Document.h"
+#include "mozilla/dom/FetchPriority.h"
 #include "nsContentUtils.h"
 #include "nsIContent.h"
 #include "nsIContentPolicy.h"
@@ -63,7 +64,7 @@ nsresult IconLoader::LoadIcon(nsIURI* aIconURI, nsINode* aNode,
         nullptr, nsIRequest::LOAD_NORMAL, nullptr,
         nsIContentPolicy::TYPE_INTERNAL_IMAGE, u""_ns,
         /* aUseUrgentStartForChannel */ false, /* aLinkPreload */ false, 0,
-        getter_AddRefs(mIconRequest));
+        dom::FetchPriority::Auto, getter_AddRefs(mIconRequest));
   } else {
     // TODO: nsIContentPolicy::TYPE_INTERNAL_IMAGE may not be the correct
     // policy. See bug 1691868 for more details.
@@ -72,7 +73,8 @@ nsresult IconLoader::LoadIcon(nsIURI* aIconURI, nsINode* aNode,
         aNode, document, nsIRequest::LOAD_NORMAL, nullptr,
         nsIContentPolicy::TYPE_INTERNAL_IMAGE, u""_ns,
         /* aUseUrgentStartForChannel */ false,
-        /* aLinkPreload */ false, 0, getter_AddRefs(mIconRequest));
+        /* aLinkPreload */ false, 0, dom::FetchPriority::Auto,
+        getter_AddRefs(mIconRequest));
   }
   if (NS_FAILED(rv)) {
     return rv;