Return the uploaded file when validator fails

You cant, the file input just cant have default value.

I guess it is for security reason. What if a malicious dev put a critical system file as default value ?

I can imagine! So do you use a hidden field that you populate if there is an image found? Or how do you go about it?

I think that if the validation is "client side" this wont happen. If the validation is server side, we can store the image path in a hidden value and return it with the validation fails state.

I can imagine! So do you use a hidden field that you populate if there is an image found? Or how do you go about it?

I do some client-side checks, and in the rare case where the user has JS disabled or the checks don't run for some reason, then I just return to the form, repopulate every field except the image - it's an inconvenience, but it rarely happens.

As it's already been pointed out, you can't manually set the value of a file input, it's read-only, for obvious security considerations.

I'm not sure what good it would do to store the image/file path in a hidden input, if you want to upload it on your own server then the user will have to submit it via the file input any ways.