diff --git a/handlers/profile.go b/handlers/profile.go
index 618fe3c..e314609 100644
--- a/handlers/profile.go
+++ b/handlers/profile.go
@@ -91,7 +91,13 @@ func UpdateProfile(db *gorm.DB, storagePath string) gin.HandlerFunc {
 				return
 			}
 
-			// Use user ID as filename base to avoid duplicates.
+			// Remove old avatar file if it exists (different extension or same).
+			if user.Avatar != "" {
+				oldPath := filepath.Join(avatarDir, user.Avatar)
+				os.Remove(oldPath) // ignore error — file may not exist
+			}
+
+			// Use user ID as filename base.
 			savedName := fmt.Sprintf("%d%s", user.ID, ext)
 			savedPath := filepath.Join(avatarDir, savedName)
 
@@ -108,7 +114,6 @@ func UpdateProfile(db *gorm.DB, storagePath string) gin.HandlerFunc {
 			}
 
 			user.Avatar = savedName
-			// Update session display immediately.
 			session.Set("avatar", savedName)
 		}