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diff --git a/testing/web-platform/tests/html/semantics/embedded-content/the-img-element/image-loading-lazy-available.html b/testing/web-platform/tests/html/semantics/embedded-content/the-img-element/image-loading-lazy-available.html
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--- /dev/null
+++ b/testing/web-platform/tests/html/semantics/embedded-content/the-img-element/image-loading-lazy-available.html
@@ -0,0 +1,30 @@
+<!doctype html>
+<title>The list of available images gets checked before deciding to make a load lazy</title>
+<link rel="help" href="https://html.spec.whatwg.org/multipage/images.html#update-the-image-data">
+<link rel="help" href="https://html.spec.whatwg.org/multipage/images.html#will-lazy-load-image-steps">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1709577">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<img src="/images/green-256x256.png">
+<div style="height:1000vh;"></div>
+<script>
+promise_test(async t => {
+  await new Promise(resolve => {
+    window.addEventListener("load", resolve);
+  });
+  let nonLazy = document.querySelector("img");
+  assert_equals(nonLazy.width, 256);
+  assert_equals(nonLazy.height, 256);
+
+  let lazy = document.createElement("img");
+  lazy.loading = "lazy";
+  lazy.src = nonLazy.src;
+  document.body.appendChild(lazy);
+
+  await new Promise(resolve => setTimeout(resolve));
+
+  assert_equals(lazy.width, 256, "The list of available images should be checked before delaying the image load");
+  assert_equals(lazy.height, 256, "The list of available images should be checked before delaying the image load");
+});
+</script>