histories are a little messed, will change the logic in the future (techdebt)

api/app/Http/Requests/RegisterRequest.php

@@ -26,7 +26,7 @@ class RegisterRequest extends FormRequest
             'nickname' => 'required|string|max:255',
             'name' => 'required|string|max:255',
             'password' => 'required|string|min:3',
-            'photo' => 'nullable|string',
+            'photo' => 'nullable|image|mimes:jpeg,png,jpg,gif|max:2048',
         ];
     }
 }