fix: correct error messages for dall-e models size parameters

(cherry picked from commit 149d06850c10cc6cdb3291164e3e46f99ca59abc)

relay/relay-image.go

@@ -49,11 +49,11 @@ func getAndValidImageRequest(c *gin.Context, info *relaycommon.RelayInfo) (*dto.
 		// Not "256x256", "512x512", or "1024x1024"
 		if imageRequest.Model == "dall-e-2" || imageRequest.Model == "dall-e" {
 			if imageRequest.Size != "" && imageRequest.Size != "256x256" && imageRequest.Size != "512x512" && imageRequest.Size != "1024x1024" {
-				return nil, errors.New("size must be one of 256x256, 512x512, or 1024x1024, dall-e-3 1024x1792 or 1792x1024")
+				return nil, errors.New("size must be one of 256x256, 512x512, or 1024x1024 for dall-e-2 or dall-e")
 			}
 		} else if imageRequest.Model == "dall-e-3" {
 			if imageRequest.Size != "" && imageRequest.Size != "1024x1024" && imageRequest.Size != "1024x1792" && imageRequest.Size != "1792x1024" {
-				return nil, errors.New("size must be one of 256x256, 512x512, or 1024x1024, dall-e-3 1024x1792 or 1792x1024")
+				return nil, errors.New("size must be one of 1024x1024, 1024x1792 or 1792x1024 for dall-e-3")
 			}
 			if imageRequest.Quality == "" {
 				imageRequest.Quality = "standard"