diff --git a/dom/base/nsImageLoadingContent.cpp b/dom/base/nsImageLoadingContent.cpp
index 98a4628dd301..4b842e155d79 100644
--- a/dom/base/nsImageLoadingContent.cpp
+++ b/dom/base/nsImageLoadingContent.cpp
@@ -54,6 +54,7 @@
 #include "mozilla/dom/ImageTracker.h"
 #include "mozilla/dom/PageLoadEventUtils.h"
 #include "mozilla/dom/ReferrerInfo.h"
+#include "mozilla/dom/ResponsiveImageSelector.h"
 #include "mozilla/dom/ScriptSettings.h"
 #include "mozilla/intl/LocaleService.h"
 #include "mozilla/intl/Locale.h"
@@ -1275,6 +1276,66 @@ already_AddRefed<Promise> nsImageLoadingContent::RecognizeCurrentImageText(
   return domPromise.forget();
 }
 
+CSSIntSize nsImageLoadingContent::NaturalSize() {
+  if (!mCurrentRequest) {
+    return {};
+  }
+
+  nsCOMPtr<imgIContainer> image;
+  mCurrentRequest->GetImage(getter_AddRefs(image));
+  if (!image) {
+    return {};
+  }
+
+  mozilla::image::ImageIntrinsicSize intrinsicSize;
+  nsresult rv = image->GetIntrinsicSize(&intrinsicSize);
+  if (NS_FAILED(rv)) {
+    return {};
+  }
+
+  CSSIntSize size;  // defaults to 0,0
+  if (!StaticPrefs::image_natural_size_fallback_enabled()) {
+    size.width = intrinsicSize.mWidth.valueOr(0);
+    size.height = intrinsicSize.mHeight.valueOr(0);
+  } else {
+    // Fallback case, for web-compatibility!
+    // See https://github.com/whatwg/html/issues/11287 and bug 1935269.
+    // If we lack an intrinsic size in either axis, then use the fallback size,
+    // unless we can transfer the size through the aspect ratio.
+    // (And if we *only* have an intrinsic aspect ratio, use the fallback width
+    // and transfer that through the aspect ratio to produce a height.)
+    size.width = intrinsicSize.mWidth.valueOr(kFallbackIntrinsicWidthInPixels);
+    size.height =
+        intrinsicSize.mHeight.valueOr(kFallbackIntrinsicHeightInPixels);
+    AspectRatio ratio = image->GetIntrinsicRatio();
+    if (ratio) {
+      if (!intrinsicSize.mHeight) {
+        // Compute the height from the width & ratio.  (Note that the width we
+        // use here might be kFallbackIntrinsicWidthInPixels, and that's fine.)
+        size.height = ratio.Inverted().ApplyTo(size.width);
+      } else if (!intrinsicSize.mWidth) {
+        // Compute the width from the height & ratio.
+        size.width = ratio.ApplyTo(size.height);
+      }
+    }
+  }
+
+  ImageResolution resolution = image->GetResolution();
+  // NOTE(emilio): What we implement here matches the image-set() spec, but it's
+  // unclear whether this is the right thing to do, see
+  // https://github.com/whatwg/html/pull/5574#issuecomment-826335244.
+  if (auto* image = HTMLImageElement::FromNode(AsContent())) {
+    if (auto* sel = image->GetResponsiveImageSelector()) {
+      float density = sel->GetSelectedImageDensity();
+      MOZ_ASSERT(density >= 0.0);
+      resolution.ScaleBy(density);
+    }
+  }
+
+  resolution.ApplyTo(size.width, size.height);
+  return size;
+}
+
 CSSIntSize nsImageLoadingContent::GetWidthHeightForImage() {
   Element* element = AsContent()->AsElement();
   if (nsIFrame* frame = element->GetPrimaryFrame(FlushType::Layout)) {
diff --git a/dom/base/nsImageLoadingContent.h b/dom/base/nsImageLoadingContent.h
index 3b090c245682..06e029b78c43 100644
--- a/dom/base/nsImageLoadingContent.h
+++ b/dom/base/nsImageLoadingContent.h
@@ -239,6 +239,12 @@ class nsImageLoadingContent : public nsIImageLoadingContent {
 
   virtual mozilla::dom::FetchPriority GetFetchPriorityForImage() const;
 
+  /**
+   * Get the natural size of the current request, as defined here:
+   * https://html.spec.whatwg.org/multipage/images.html#preferred-density-corrected-dimensions
+   */
+  mozilla::CSSIntSize NaturalSize();
+
   /**
    * Get width and height of the current request, using given image request if
    * attributes are unset.
diff --git a/dom/html/HTMLImageElement.cpp b/dom/html/HTMLImageElement.cpp
index 124aa331de26..06fb2ce1ff5e 100644
--- a/dom/html/HTMLImageElement.cpp
+++ b/dom/html/HTMLImageElement.cpp
@@ -612,64 +612,6 @@ uint32_t HTMLImageElement::Height() { return GetWidthHeightForImage().height; }
 
 uint32_t HTMLImageElement::Width() { return GetWidthHeightForImage().width; }
 
-CSSIntSize HTMLImageElement::NaturalSize() {
-  if (!mCurrentRequest) {
-    return {};
-  }
-
-  nsCOMPtr<imgIContainer> image;
-  mCurrentRequest->GetImage(getter_AddRefs(image));
-  if (!image) {
-    return {};
-  }
-
-  mozilla::image::ImageIntrinsicSize intrinsicSize;
-  nsresult rv = image->GetIntrinsicSize(&intrinsicSize);
-  if (NS_FAILED(rv)) {
-    return {};
-  }
-
-  CSSIntSize size;  // defaults to 0,0
-  if (!StaticPrefs::image_natural_size_fallback_enabled()) {
-    size.width = intrinsicSize.mWidth.valueOr(0);
-    size.height = intrinsicSize.mHeight.valueOr(0);
-  } else {
-    // Fallback case, for web-compatibility!
-    // See https://github.com/whatwg/html/issues/11287 and bug 1935269.
-    // If we lack an intrinsic size in either axis, then use the fallback size,
-    // unless we can transfer the size through the aspect ratio.
-    // (And if we *only* have an intrinsic aspect ratio, use the fallback width
-    // and transfer that through the aspect ratio to produce a height.)
-    size.width = intrinsicSize.mWidth.valueOr(kFallbackIntrinsicWidthInPixels);
-    size.height =
-        intrinsicSize.mHeight.valueOr(kFallbackIntrinsicHeightInPixels);
-    AspectRatio ratio = image->GetIntrinsicRatio();
-    if (ratio) {
-      if (!intrinsicSize.mHeight) {
-        // Compute the height from the width & ratio.  (Note that the width we
-        // use here might be kFallbackIntrinsicWidthInPixels, and that's fine.)
-        size.height = ratio.Inverted().ApplyTo(size.width);
-      } else if (!intrinsicSize.mWidth) {
-        // Compute the width from the height & ratio.
-        size.width = ratio.ApplyTo(size.height);
-      }
-    }
-  }
-
-  ImageResolution resolution = image->GetResolution();
-  // NOTE(emilio): What we implement here matches the image-set() spec, but it's
-  // unclear whether this is the right thing to do, see
-  // https://github.com/whatwg/html/pull/5574#issuecomment-826335244.
-  if (mResponsiveSelector) {
-    float density = mResponsiveSelector->GetSelectedImageDensity();
-    MOZ_ASSERT(density >= 0.0);
-    resolution.ScaleBy(density);
-  }
-
-  resolution.ApplyTo(size.width, size.height);
-  return size;
-}
-
 nsresult HTMLImageElement::CopyInnerTo(HTMLImageElement* aDest) {
   MOZ_TRY(nsGenericHTMLElement::CopyInnerTo(aDest));
 
diff --git a/dom/html/HTMLImageElement.h b/dom/html/HTMLImageElement.h
index e9d14575d18e..ba94e1ad1efc 100644
--- a/dom/html/HTMLImageElement.h
+++ b/dom/html/HTMLImageElement.h
@@ -94,7 +94,6 @@ class HTMLImageElement final : public nsGenericHTMLElement,
     SetUnsignedIntAttr(nsGkAtoms::height, aHeight, 0, aError);
   }
 
-  CSSIntSize NaturalSize();
   uint32_t NaturalHeight() { return NaturalSize().height; }
   uint32_t NaturalWidth() { return NaturalSize().width; }