Internal error when uploading a picture without selecting a file

[jiru]

To Reproduce
Steps to reproduce the behavior:

1. Login and got to your profile.
2. Click the edit button.
3. You are now on the edit page.
4. Click on the upload button on the top-right area. (Note that no file was selected!)
5. See error: An internal error has occurred.

Expected behavior

5. Same as what it used to be: the profile page should display again along with a flash message that says "Failed to upload image".