diff --git a/devtools/client/netmonitor/test/browser_net_copy_headers.js b/devtools/client/netmonitor/test/browser_net_copy_headers.js
index f82ccfcc8a9f..e5bd2bfee251 100644
--- a/devtools/client/netmonitor/test/browser_net_copy_headers.js
+++ b/devtools/client/netmonitor/test/browser_net_copy_headers.js
@@ -42,7 +42,7 @@ add_task(async function () {
     `${method} ${SIMPLE_URL.split("example.com")[1]} ${httpVersion}`,
     "Host: example.com",
     "User-Agent: " + navigator.userAgent + "",
-    "Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/png,image/svg+xml,*/*;q=0.8",
+    "Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8",
     "Accept-Language: " + navigator.languages.join(",") + ";q=0.5",
     "Accept-Encoding: gzip, deflate",
     "Connection: keep-alive",
diff --git a/dom/tests/browser/browser_persist_image_accept.js b/dom/tests/browser/browser_persist_image_accept.js
index 24675a4469b7..21a2096b9dea 100644
--- a/dom/tests/browser/browser_persist_image_accept.js
+++ b/dom/tests/browser/browser_persist_image_accept.js
@@ -51,7 +51,7 @@ function expectedImageAcceptHeader() {
   return (
     (Services.prefs.getBoolPref("image.avif.enabled") ? "image/avif," : "") +
     (Services.prefs.getBoolPref("image.jxl.enabled") ? "image/jxl," : "") +
-    "image/webp,image/png,image/svg+xml,image/*;q=0.8,*/*;q=0.5"
+    "image/webp,*/*"
   );
 }
 
diff --git a/image/test/mochitest/bug496292-1.sjs b/image/test/mochitest/bug496292-1.sjs
index f10de708e4c5..2e842223d551 100644
--- a/image/test/mochitest/bug496292-1.sjs
+++ b/image/test/mochitest/bug496292-1.sjs
@@ -6,10 +6,7 @@ function handleRequest(request, response) {
   file.append("test");
   file.append("mochitest");
 
-  if (
-    request.getHeader("Accept") ==
-    "image/avif,image/webp,image/png,image/svg+xml,image/*;q=0.8,*/*;q=0.5"
-  ) {
+  if (request.getHeader("Accept") == "image/avif,image/webp,*/*") {
     file.append("blue.png");
   } else {
     file.append("red.png");
diff --git a/netwerk/protocol/http/nsHttpHandler.cpp b/netwerk/protocol/http/nsHttpHandler.cpp
index 068926844af7..782f2893ff12 100644
--- a/netwerk/protocol/http/nsHttpHandler.cpp
+++ b/netwerk/protocol/http/nsHttpHandler.cpp
@@ -216,33 +216,17 @@ static nsCString ImageAcceptHeader() {
     mimeTypes.Append("image/jxl,");
   }
 
-  mimeTypes.Append("image/webp,");
-
-  // Default value as specified by fetch standard
-  // https://fetch.spec.whatwg.org/commit-snapshots/8dd73dbecfefdbef8f432164fb3a5b9785f7f520/#ref-for-header-list-contains%E2%91%A7
-  mimeTypes.Append("image/png,image/svg+xml,image/*;q=0.8,*/*;q=0.5");
+  mimeTypes.Append("image/webp,*/*");
 
   return mimeTypes;
 }
 
-static nsCString DocumentAcceptHeader() {
-  // https://fetch.spec.whatwg.org/#document-accept-header-value
-  // The value specified by the fetch standard is
-  // `text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8`
-  // but we also insert all of the image formats before */*
-  nsCString mimeTypes("text/html,application/xhtml+xml,application/xml;q=0.9,");
+static nsCString DocumentAcceptHeader(const nsCString& aImageAcceptHeader) {
+  nsPrintfCString mimeTypes(
+      "text/html,application/xhtml+xml,application/xml;q=0.9,%s;q=0.8",
+      aImageAcceptHeader.get());
 
-  if (mozilla::StaticPrefs::image_avif_enabled()) {
-    mimeTypes.Append("image/avif,");
-  }
-
-  if (mozilla::StaticPrefs::image_jxl_enabled()) {
-    mimeTypes.Append("image/jxl,");
-  }
-
-  mimeTypes.Append("image/webp,image/png,image/svg+xml,*/*;q=0.8");
-
-  return mimeTypes;
+  return std::move(mimeTypes);
 }
 
 nsHttpHandler::nsHttpHandler()
@@ -251,7 +235,7 @@ nsHttpHandler::nsHttpHandler()
           PR_SecondsToInterval(StaticPrefs::network_http_http2_timeout())),
       mResponseTimeout(PR_SecondsToInterval(300)),
       mImageAcceptHeader(ImageAcceptHeader()),
-      mDocumentAcceptHeader(DocumentAcceptHeader()),
+      mDocumentAcceptHeader(DocumentAcceptHeader(ImageAcceptHeader())),
       mLastUniqueID(NowInSeconds()),
       mDebugObservations(false),
       mEnableAltSvc(false),
@@ -1763,7 +1747,7 @@ void nsHttpHandler::PrefsChanged(const char* pref) {
     }
 
     if (userSetDocumentAcceptHeader.IsEmpty()) {
-      mDocumentAcceptHeader.Assign(DocumentAcceptHeader());
+      mDocumentAcceptHeader.Assign(DocumentAcceptHeader(mImageAcceptHeader));
     } else {
       mDocumentAcceptHeader.Assign(userSetDocumentAcceptHeader);
     }
diff --git a/netwerk/test/mochitests/test_accept_header.html b/netwerk/test/mochitests/test_accept_header.html
index 977c531dcffc..0acae2a825bb 100644
--- a/netwerk/test/mochitests/test_accept_header.html
+++ b/netwerk/test/mochitests/test_accept_header.html
@@ -26,7 +26,7 @@ function test_iframe() {
   let ifr = document.createElement("iframe");
   ifr.src = "test_accept_header.sjs?iframe";
   ifr.onload = () => {
-    test_last_request_and_continue("iframe", "text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/png,image/svg+xml,*/*;q=0.8");
+    test_last_request_and_continue("iframe", "text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8");
   };
   document.body.appendChild(ifr);
 }
@@ -36,7 +36,7 @@ function test_image() {
   i.src = "test_accept_header.sjs?image";
   i.onload = function() {
     // Fetch spec says we should have: "image/png,image/svg+xml,image/*;q=0.8,*/*;q=0.5"
-    test_last_request_and_continue("image", "image/avif,image/webp,image/png,image/svg+xml,image/*;q=0.8,*/*;q=0.5");
+    test_last_request_and_continue("image", "image/avif,image/webp,*/*");
   }
 }