title: What's the best way to implement a user-friendly form with image fields?
body: <p>I want to implement a register form with some heavy fields like images fields (to upload).</p>
  
  <p>When not using AJAX, the entire form is sent to the server, including the images. That can be very time consuming, and if the form is invalid, the user is forced to upload the form again. This is not user friendly.</p>
  
  <p>So, I think AJAX can be a solution. But how could be the best way to do it?
  The images should be uploaded once, and it should be needed to upload them again if they are invalid (size exceeded, incorrect format, …).</p>
  
  <p>Would it be worth to implement it in a unobstrusive way? (should everything work when javascript is disabled?)</p>