title: Can't get a UIImageView fill the parent UIView with autolayout
body: <p>I'm trying to fill a UIView with a UIImageView using auto layout. I've tried several thing, but the most obvious, equalSize with parent view only works when I set the correct size in "Simulated metric". If I let Freeform (the point of autolayout isn't it ?) I get messed up.</p>
  
  <p>I'm testing on an iPhone 4S and a 6 plus.</p>
  
  <p>Thanks for any leading tracks.</p>
  
  <p>EDIT FOR @mittens</p>
  
  <p><img src="https://i.stack.imgur.com/QqV1X.png" alt="enter image description here"></p>
  
  <p><img src="https://i.stack.imgur.com/zyhCX.png" alt="enter image description here"></p>
  
  <p>I've seen your edit. I still can get it working. As you see I have 4 margin constraints, the same as in your code (I did not need the rest because I only use the main UIView).
  Anyway, when I change the size on xcode, the layout is perfect, when I send it to my 4S, I only get Top and left margins.</p>