diff --git a/apps/backend/src/lib/images.tsx b/apps/backend/src/lib/images.tsx
index c63ae05c9..15bf995aa 100644
--- a/apps/backend/src/lib/images.tsx
+++ b/apps/backend/src/lib/images.tsx
@@ -28,12 +28,12 @@ export async function parseBase64Image(input: string, options: {
   try {
     imageBuffer = Buffer.from(base64Data, 'base64');
   } catch (error) {
-    throw new Error('Invalid base64 image data');
+    throw new ImageProcessingError('Invalid base64 image data');
   }
 
   // Check file size
   if (options.maxBytes && imageBuffer.length > options.maxBytes) {
-    throw new Error(`Image size (${imageBuffer.length} bytes) exceeds maximum allowed size (${options.maxBytes} bytes)`);
+    throw new ImageProcessingError(`Image size (${imageBuffer.length} bytes) exceeds maximum allowed size (${options.maxBytes} bytes)`);
   }
 
   // Dynamically import sharp
diff --git a/apps/backend/src/s3.tsx b/apps/backend/src/s3.tsx
index 561c354bd..168c3c579 100644
--- a/apps/backend/src/s3.tsx
+++ b/apps/backend/src/s3.tsx
@@ -29,7 +29,7 @@ export function getS3PublicUrl(key: string): string {
   return `${S3_ENDPOINT}/${S3_BUCKET}/${key}`;
 }
 
-export async function uploadBase64Image({
+async function uploadBase64Image({
   input,
   maxBytes = 1024 * 300,
   folderName,
@@ -42,7 +42,14 @@ export async function uploadBase64Image({
     throw new StackAssertionError("S3 is not configured");
   }
 
-  const { buffer, metadata } = await parseBase64Image(input, { maxBytes });
+  try {
+    const { buffer, metadata } = await parseBase64Image(input, { maxBytes });
+  } catch (error) {
+    if (error instanceof ImageProcessingError) {
+      throw new StatusError(StatusError.BadRequest, error.message);
+    }
+    throw error;
+  }
 
   const key = `${folderName}/${crypto.randomUUID()}.${metadata.format}`;