diff --git a/.changeset/happy-mayflies-sort.md b/.changeset/happy-mayflies-sort.md
new file mode 100644
index 000000000..2038ea1b3
--- /dev/null
+++ b/.changeset/happy-mayflies-sort.md
@@ -0,0 +1,5 @@
+---
+'@astrojs/image': patch
+---
+
+Fix image external config in build
diff --git a/packages/integrations/image/src/index.ts b/packages/integrations/image/src/index.ts
index 24e70a35d..e3770d5e9 100644
--- a/packages/integrations/image/src/index.ts
+++ b/packages/integrations/image/src/index.ts
@@ -52,7 +52,7 @@ export default function integration(options: IntegrationOptions = {}): AstroInte
 	// During SSG builds, this is used to track all transformed images required.
 	const staticImages = new Map<string, Map<string, TransformOptions>>();
 
-	function getViteConfiguration() {
+	function getViteConfiguration(isDev: boolean) {
 		return {
 			plugins: [createPlugin(_config, resolvedOptions)],
 			build: {
@@ -62,8 +62,9 @@ export default function integration(options: IntegrationOptions = {}): AstroInte
 			},
 			ssr: {
 				noExternal: ['@astrojs/image', resolvedOptions.serviceEntryPoint],
-				// CJS dependencies used by `serviceEntryPoint`
-				external: ['http-cache-semantics', 'image-size', 'mime'],
+				// Externalize CJS dependencies used by `serviceEntryPoint`. Vite dev mode has trouble
+				// loading these modules with `ssrLoadModule`, but works in build.
+				external: isDev ? ['http-cache-semantics', 'image-size', 'mime'] : [],
 			},
 			assetsInclude: ['**/*.wasm'],
 		};
@@ -75,7 +76,7 @@ export default function integration(options: IntegrationOptions = {}): AstroInte
 			'astro:config:setup': async ({ command, config, updateConfig, injectRoute }) => {
 				needsBuildConfig = !config.build?.server;
 				_config = config;
-				updateConfig({ vite: getViteConfiguration() });
+				updateConfig({ vite: getViteConfiguration(command === 'dev') });
 
 				if (command === 'dev' || config.output === 'server') {
 					injectRoute({