Assign POST value to Form "file" field

I have a page that renders a form, then POSTs back to itself to validate/save the data. The form includes a “file” field for uploading an image (actually, it has several). If there are errors in validation (blank required fields for example), I reassign the previously entered values back to the form fields. That works for all except the “file” fields.

I understand about not being able to assign values in JavaScript (for security reasons), but does that apply to PHP as well? If so, why? Is there a way to do what I’ve described?

Also in #PHP _↴