@@ -249,6 +249,30 @@ it("loads the <picture> source for the current theme through the image route", a
     .toHaveAttribute("src", `${pixel}#/work/dark.png`);
 });
 
+it("sizes a raw HTML image by width and height written with px units", async () => {
+  setup();
+  const largeImage = `data:image/svg+xml,${encodeURIComponent(
+    '<svg xmlns="http://www.w3.org/2000/svg" width="200" height="200"/>',
+  )}`;
+  await using screen = await render(
+    <HostImageUrlContext value={() => largeImage}>
+      <ChatMarkdown
+        cwd={undefined}
+        parseRawHtml
+        text={
+          '### PR Review in progress <img src="/work/spinner.gif" alt="spinner" width="14px" height="7px" />'
+        }
+      />
+    </HostImageUrlContext>,
+  );
+  const image = screen.getByAltText("spinner");
+  await expect.element(image).toHaveAttribute("src", largeImage);
+  const element = image.element() as HTMLImageElement;
+  await element.decode();
+  const { width, height } = element.getBoundingClientRect();
+  expect({ width, height }).toEqual({ width: 14, height: 7 });
+});
+
 it("reuses the parse of a streaming reply's finished blocks when it remounts", async () => {
   setup();
   const message = (
 
@@ -52,6 +52,10 @@ function markdownDestination(src: string): string {
   return `<${escaped}>`;
 }
 
+function parseImageDimension(value: string | number | undefined): number {
+  return Number(typeof value === "string" ? value.trim().replace(/px$/i, "") : value);
+}
+
 /**
  * `maxHeightRem` folds a height cap into the width bound: `max-height` alone
  * would not feed back through `aspect-ratio` once `width` is definite, so a
@@ -62,8 +66,8 @@ export function authoredImageSizeStyle(
   height: string | number | undefined,
   maxHeightRem = 30,
 ): CSSProperties | undefined {
-  const parsedWidth = Number(width);
-  const parsedHeight = Number(height);
+  const parsedWidth = parseImageDimension(width);
+  const parsedHeight = parseImageDimension(height);
   const hasWidth = Number.isFinite(parsedWidth) && parsedWidth > 0;
   const hasHeight = Number.isFinite(parsedHeight) && parsedHeight > 0;
   if (hasWidth && hasHeight) {