add node example to open graph image docs (#64305)

### What?

Adds a Node.js example for using assets with `ImageResponse` to create
og images.

### Why?

The only examples available use `new URL` and `fetch` which does not
work when the runtime is using Node.js.

---------

Co-authored-by: Delba de Oliveira <[email protected]>

docs/02-app/02-api-reference/02-file-conventions/01-metadata/opengraph-image.mdx

@@ -392,6 +392,65 @@ export default async function Image({ params }) {
 }
 ```
 
+#### Using Edge runtime with local assets
+
+This example uses the Edge runtime to fetch a local image on the file system and passes it as an `ArrayBuffer` to the `src` attribute of an `<img>` element.
+
+```jsx filename="app/opengraph-image.js" switcher
+import { ImageResponse } from 'next/og'
+import { readFile } from 'node:fs/promises'
+
+export const runtime = 'edge'
+
+export async function GET() {
+  const logoSrc = await fetch(new URL('./logo.png', import.meta.url)).then(
+    (res) => res.arrayBuffer()
+  )
+
+  return new ImageResponse(
+    (
+      <div
+        style={{
+          display: 'flex',
+          alignItems: 'center',
+          justifyContent: 'center',
+        }}
+      >
+        <img src={logoSrc} height="100" />
+      </div>
+    )
+  )
+}
+```
+
+#### Using Node.js runtime with local assets
+
+This example uses the Node.js runtime to fetch a local image on the file system and passes it as an `ArrayBuffer` to the `src` attribute of an `<img>` element.
+
+```jsx filename="app/opengraph-image.js" switcher
+import { ImageResponse } from 'next/og'
+import { readFile } from 'node:fs/promises'
+
+export async function GET() {
+  const logoData = await readFile('./logo.png')
+  const logoSrc = Uint8Array.from(logoData).buffer
+
+  return new ImageResponse(
+    (
+      <div
+        style={{
+          display: 'flex',
+          alignItems: 'center',
+          justifyContent: 'center',
+        }}
+      >
+        <img src={logoSrc} height="100" />
+      </div>
+    )
+  )
+}
+```
+
 ## Version History
 
 | Version   | Changes                                           |