JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
Unfortunately, I am not sure about the reason behind this issue. When I clone your form, it does submit the image on my side.
Could you please clone the form, and test the cloned version to see if that makes any difference on your end?