diff --git a/backend/src/main/java/com/funeat/common/s3/S3Uploader.java b/backend/src/main/java/com/funeat/common/s3/S3Uploader.java
index 765f188a4..dd0bc062e 100644
--- a/backend/src/main/java/com/funeat/common/s3/S3Uploader.java
+++ b/backend/src/main/java/com/funeat/common/s3/S3Uploader.java
@@ -57,7 +57,12 @@ private void validateExtension(final MultipartFile image) {
     }
 
     private String getKey(final MultipartFile image) {
-        return folder + getRandomImageName(image);
+        return folder + getRandomImageName(image) + "." + getFormat(image);
+    }
+
+    private String getFormat(final MultipartFile image) {
+        final String contentType = image.getContentType();
+        return contentType.substring(contentType.lastIndexOf("/") + 1);
     }
 
     private String getRandomImageName(final MultipartFile image) {