Fix bare images used in JSON content collections (#14590)

* fix(content): normalize bare filenames in content layer image() helper

Fixes #14456

The image() helper in content layer collections now normalizes bare
filenames (e.g., "cover.jpg") to relative paths (e.g., "./cover.jpg")
to ensure consistent resolution behavior with markdown frontmatter.

Without this normalization, bare filenames were passed directly to
Vite's resolver, which treated them as package imports rather than
relative file references, causing resolution failures.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

* test(content): add test for bare filename images in JSON collections

Adds a test case to verify that bare filenames (e.g., "cover.jpg")
work correctly in JSON content layer collections with the image()
helper, ensuring they are resolved the same way as in markdown
frontmatter.

The test includes:
- New rockets.json fixture with bare filename and relative path images
- Test assertions for both bare filename and relative path resolution
- Updated collections.json.js to include the new collection

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

* chore: add changeset for image path resolution fix

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

* fix(content): exclude aliases and parent paths from normalization

Updates the bare filename normalization to properly skip:
- Alias paths starting with ~ (e.g., ~/assets/image.jpg)
- Alias paths starting with @ (e.g., @images/image.jpg)
- Parent directory paths starting with ../ (e.g., ../image.jpg)

This prevents breaking existing alias resolution while still
normalizing true bare filenames like "cover.jpg" to "./cover.jpg".

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

---------

Co-authored-by: Claude <[email protected]>

Author: matthewp

.changeset/neat-images-resolve.md

@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fixes image path resolution in content layer collections to support bare filenames. The `image()` helper now normalizes bare filenames like `"cover.jpg"` to relative paths `"./cover.jpg"` for consistent resolution behavior between markdown frontmatter and JSON content collections.

packages/astro/src/content/utils.ts

@@ -184,8 +184,27 @@ export async function getEntryDataAndImages<
 			schema = schema({
 				image: () =>
 					z.string().transform((val) => {
-						imageImports.add(val);
-						return `${IMAGE_IMPORT_PREFIX}${val}`;
+						// Normalize bare filenames to relative paths for consistent resolution
+						// This ensures bare filenames like "cover.jpg" work the same way as in markdown frontmatter
+						// Skip normalization for:
+						// - Relative paths (./foo, ../foo)
+						// - Absolute paths (/foo)
+						// - URLs (http://...)
+						// - Aliases (~/, @/, etc.)
+						let normalizedPath = val;
+						if (
+							val &&
+							!val.startsWith('./') &&
+							!val.startsWith('../') &&
+							!val.startsWith('/') &&
+							!val.startsWith('~') &&
+							!val.startsWith('@') &&
+							!val.includes('://')
+						) {
+							normalizedPath = `./${val}`;
+						}
+						imageImports.add(normalizedPath);
+						return `${IMAGE_IMPORT_PREFIX}${normalizedPath}`;
 					}),
 			});
 		}

packages/astro/test/content-layer.test.js

@@ -281,6 +281,16 @@ describe('Content Layer', () => {
 			assert.ok(json.images[1].data.image.startsWith('https://'));
 		});
 
+		it('loads images with bare filenames in JSON', async () => {
+			assert.ok(json.rockets[0].data.image.src.startsWith('/_astro'));
+			assert.equal(json.rockets[0].data.image.format, 'jpg');
+		});
+
+		it('loads images with relative paths in JSON', async () => {
+			assert.ok(json.rockets[1].data.image.src.startsWith('/_astro'));
+			assert.equal(json.rockets[1].data.image.format, 'jpg');
+		});
+
 		it('renders images from frontmatter', async () => {
 			assert.ok($('img[alt="Lunar Module"]').attr('src').startsWith('/_astro'));
 		});

packages/astro/test/fixtures/content-layer/src/content.config.ts

@@ -253,6 +253,17 @@ const songs = defineCollection({
         }),
 });
 
+const rockets = defineCollection({
+	loader: file('src/data/rockets.json'),
+	schema: ({ image }) =>
+		z.object({
+			id: z.string(),
+			name: z.string(),
+			manufacturer: z.string(),
+			image: image(),
+		}),
+});
+
 export const collections = {
 	blog,
 	dogs,
@@ -270,6 +281,7 @@ export const collections = {
 	songs,
 	probes,
 	rodents,
+	rockets,
 	notADirectory,
 	nothingMatches
 };

packages/astro/test/fixtures/content-layer/src/data/rockets.json

@@ -0,0 +1,14 @@
+[
+  {
+    "id": "falcon-9",
+    "name": "Falcon 9",
+    "manufacturer": "SpaceX",
+    "image": "shuttle.jpg"
+  },
+  {
+    "id": "saturn-v",
+    "name": "Saturn V",
+    "manufacturer": "NASA",
+    "image": "./shuttle.jpg"
+  }
+]

packages/astro/test/fixtures/content-layer/src/data/shuttle.jpg

@@ -34,7 +34,9 @@ export async function GET() {
 	const nestedJsonLoader = await getCollection('birds');
 
 	const csvLoader = await getCollection('plants');
-	
+
+	const rockets = await getCollection('rockets');
+
 	const numbers = await getCollection('numbers');
 
 	const numbersYaml = await getCollection('numbersYaml');
@@ -55,7 +57,8 @@ export async function GET() {
 			numbers,
 			numbersYaml,
 			numbersToml,
-			images, 
+			images,
+			rockets,
 			probes,
 			yamlLoader,
 			tomlLoader,