diff --git a/packages/email-renderer/package.json b/packages/email-renderer/package.json
index dd62ef9b..77114d5f 100644
--- a/packages/email-renderer/package.json
+++ b/packages/email-renderer/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@wrnexus/email-renderer",
-  "version": "0.1.21",
+  "version": "0.1.22",
   "type": "module",
   "description": "WRNexus block email renderers with HTML, text, AMP Email, and MJML interoperability.",
   "exports": {
diff --git a/packages/email-renderer/src/blocks.ts b/packages/email-renderer/src/blocks.ts
index 960b3832..15e3105c 100644
--- a/packages/email-renderer/src/blocks.ts
+++ b/packages/email-renderer/src/blocks.ts
@@ -49,13 +49,13 @@ export function ampLayoutCss(node: BlockNode): string {
   return "";
 }
 const multilineText = (value: unknown) => html(value).replace(/\r\n?|\n/g, "<br />");
-const imageDimension = (fallback: string): ValueSchema<string> => ({
+const imageDimension = (fallback: string, minimum = 1): ValueSchema<string> => ({
   kind: "string",
   defaultValue: fallback,
   parse(value = fallback, path = "value") {
-    return typeof value === "string" && /^\d{1,4}$/.test(value) && Number(value) > 0 && Number(value) <= 4000
+    return typeof value === "string" && /^\d{1,4}$/.test(value) && Number(value) >= minimum && Number(value) <= 4000
       ? { ok: true, value }
-      : { ok: false, errors: [{code:"email.image-dimension",message:"Image dimensions must be between 1 and 4000 pixels.",severity:"error",path}] };
+      : { ok: false, errors: [{code:"email.image-dimension",message:`Dimensions must be between ${minimum} and 4000 pixels.`,severity:"error",path}] };
   },
 });
 const marketingImage = (node: BlockNode, target: "html" | "amp" | "mjml") => {
@@ -328,8 +328,8 @@ export const imageBlock = leaf(
   object({
     src: safeUrl({ schemes: ["https"] }),
     alt: string({ max: 1_000, default: "" }),
-    width: string({ default: "600" }),
-    height: string({ default: "300" }),
+    width: imageDimension("600"),
+    height: imageDimension("300"),
     decorative: boolean(false),
   }) as never,
   {
@@ -391,7 +391,7 @@ export const spacerBlock = leaf(
   "content.spacer",
   "Spacer",
   "icon-[lucide--move-vertical]",
-  object({ height: string({ default: "24" }) }) as never,
+  object({ height: imageDimension("24", 0) }) as never,
   {
     emailHtml: ({ node }) =>
       emailCell(
@@ -413,8 +413,8 @@ export const videoBlock = leaf(
     href: safeUrl({ schemes: ["https"] }),
     thumbnail: safeUrl({ schemes: ["https"] }),
     alt: string({ max: 1_000, default: "Video thumbnail" }),
-    width: string({ default: "600" }),
-    height: string({ default: "338" }),
+    width: imageDimension("600"),
+    height: imageDimension("338"),
   }) as never,
   {
     emailHtml: ({ node }) => emailCell(`<a href="${html(attrs(node).href)}" aria-label="${html(attrs(node).title)}"><img src="${html(attrs(node).thumbnail)}" alt="${html(attrs(node).alt)}" width="${html(attrs(node).width)}" height="${html(attrs(node).height)}" style="border:0;display:block;height:auto;width:100%;max-width:${html(attrs(node).width)}px;" /></a>`, node),
diff --git a/packages/email-renderer/test/marketing-images.test.ts b/packages/email-renderer/test/marketing-images.test.ts
index 9fd595ec..e41698d2 100644
--- a/packages/email-renderer/test/marketing-images.test.ts
+++ b/packages/email-renderer/test/marketing-images.test.ts
@@ -54,7 +54,7 @@ test("product and RSS images survive HTML, AMP and strict MJML exports", async (
     const result = await renderEmail(document(type, props), { amp: true, mjml: true });
     expect(result.ok).toBe(true);
     if (!result.ok) continue;
-    expect(result.value.parts.html.content).toContain('width:100%;max-width:320px;');
+    expect(result.value.parts.html.content).toContain("width:100%;max-width:320px;");
     for (const output of [
       result.value.parts.html.content,
       result.value.parts.amp?.content,
@@ -113,3 +113,39 @@ test("marketing image dimensions reject invalid or injected values", async () =>
     expect(result.ok).toBe(false);
   }
 });
+
+test("basic images, video thumbnails and spacers validate dimensions before rendering", async () => {
+  const cases: Array<{ type: string; props: Record<string, string> }> = [
+    { type: "content.image", props: { src: "https://example.com/image.png", alt: "Image" } },
+    {
+      type: "content.video",
+      props: {
+        href: "https://example.com/video",
+        thumbnail: "https://example.com/image.png",
+        title: "Video",
+        alt: "Video",
+      },
+    },
+    { type: "content.spacer", props: {} },
+  ];
+  for (const block of cases) {
+    for (const height of ["-1", "4001", "100%", "24;position:fixed", '24" onload="bad', "1e3"]) {
+      const result = await renderEmail(
+        document(block.type, { ...block.props, height } as Record<string, string>),
+      );
+      expect(result.ok).toBe(false);
+    }
+    const valid = await renderEmail(
+      document(block.type, { ...block.props, height: "4000" } as Record<string, string>),
+    );
+    expect(valid.ok).toBe(true);
+  }
+  expect((await renderEmail(document("content.spacer", { height: "0" }))).ok).toBe(true);
+  expect(
+    (
+      await renderEmail(
+        document("content.image", { src: "https://example.com/image.png", height: "0" }),
+      )
+    ).ok,
+  ).toBe(false);
+});