check if body is empty in upload route

main.go

@@ -113,6 +113,10 @@ func main() {
 			return fmt.Errorf("failed to read request body: %v", err)
 		}
 
+		if len(data) == 0 {
+			return srv.Error("empty body", nil, 400)
+		}
+
 		img := &model.Image{
 			UserID:      user.ID,
 			Data:        data,