Document Cloudflare binding build-time image optimization

src/content/docs/en/guides/integrations-guide/cloudflare.mdx

@@ -116,7 +116,7 @@ It also accepts the following:
 ### `imageService`
 
 <p>
-**Type:** `'passthrough' | 'cloudflare' | 'cloudflare-binding' | 'compile' | 'custom' | { build: 'compile', runtime?: 'cloudflare-binding' | 'passthrough' }`<br />
+**Type:** `'passthrough' | 'cloudflare' | 'cloudflare-binding' | 'compile' | 'custom' | { build: 'compile', runtime?: 'cloudflare-binding' | 'passthrough' } | { build: 'cloudflare-binding', runtime?: 'cloudflare-binding' | 'passthrough' }`<br />
 **Default:** `'cloudflare-binding'`
 </p>
 
@@ -128,7 +128,11 @@ Determines which image service is used by the adapter. The adapter will default
 - **`compile`:** Uses the [configured image service](/en/reference/configuration-reference/#imageservice) or falls back to a combination of internal dependencies to transform images locally at build time for prerendered routes. The noop `passthrough` option is configured for on-demand rendered pages.
 - **`custom`:** Uses the [configured image service](/en/reference/configuration-reference/#imageservice) (defaults to Sharp) to process assets at build time for prerendered routes. Bundles the image service for runtime image handling, without checking its compatibility with Cloudflare's `workerd` runtime.
 
-It is also possible to configure your image service as an object, setting both a build time and runtime service independently. Currently, `'compile'` is the only available build-time option. The supported runtime options are `'passthrough'` (default) and `'cloudflare-binding'`:
+<p><Since v="14.2.0" pkg="@astrojs/cloudflare" /></p>
+
+You can also configure the image service as an object by providing a build-time service (`compile` or `cloudflare-binding`) and, optionally, a runtime service (`passthrough` or `cloudflare-binding`).
+
+When the runtime service is omitted, its default value depends on the configured build-time service. It falls back to `'passthrough'` for `build: 'compile'` and to `'cloudflare-binding'` for `build: 'cloudflare-binding'`.
 
 ```js title="astro.config.mjs" ins={6}
 import { defineConfig } from 'astro/config';
@@ -141,6 +145,21 @@ export default defineConfig({
 });
 ```
 
+Using `imageService: 'cloudflare-binding'` enables image optimization using the [Cloudflare Images binding](https://developers.cloudflare.com/images/transform-images/bindings/) only at runtime.
+
+To opt in to build-time image optimization with the binding during `workerd` prerendering, set `build` to `'cloudflare-binding'`. If the binding fails to transform an image at build time, the adapter falls back to the [configured image service](/en/reference/configuration-reference/#imageservice) (defaults to Sharp).
+
+```js title="astro.config.mjs" ins={6}
+import { defineConfig } from 'astro/config';
+import cloudflare from '@astrojs/cloudflare';
+
+export default defineConfig({
+  adapter: cloudflare({
+    imageService: { build: 'cloudflare-binding', runtime: 'cloudflare-binding' }
+  }),
+});
+```
+
 ### `sessionKVBindingName`
 
 <p>