Glitch when filling up form on phone

I've tried testing my online form on laptops and there's no problem, but on mobile phones it can get a little glitchy. Like for example, when I try to upload an image but it's the wrong image, and i press 'back', the form refreshes and I have to fill it up from scratch. Does that happen often? 

I cloned your form to test it and was not able to reproduce the issue, at least on an emulator.  When I uploaded images through the form, the image that was selected was the image that was uploaded.  When I return to the previous page using the back button, the file that was uploaded remains the same and the data is retained. 

Does this behavior remain if you try a different browser?  Chrome or FireFox on mobile tend to work best.