Is it possible to show a message to the user when their file name isn't allowed?

Right now when you upload an image with a file name that's not allowed (say with an extra period in it, like a Mac OS screenshot), there is no message as that there was an problem. I've had 3 clients come to me asking why their image isn't uploading and a simple message would solve this issue and avoid the support request.

This is this question again: https://forum.grabaperch.com/forum/08-30-2016-images-with-periods-in-the-filename-fail-to-upload-but-no-message