Getting an invalid extension error

Form: https://form.jotform.com/60076404142142

I've tried multiple extension listings for the upload file buttons, including capitalized and not capitalized, with a dot before the extension and without, still getting the following error for all buttons: 

"Levin0943751.jpg has invalid extension. Only are allowed." 

I was able to upload PNG and JPG files with no problem in your form. I did it opening the direct link of it http://www.jotform.us/form/60076404142142

Here is the proof of my testing:

Is this problem happening in the embed version? The URL that you shared above does not show a form.  If this is the case, please embed the form using the iFrame method. because the problem might be caused by a conflict between the scripts codes in your page and the jotform.