title: Width and Horizontal Position Are Ambiguous
body: <p>it seems I have created a simple Image view with the following constraints:</p>
  
  <p>Align Center X to: <strong>Superview</strong></p>
  
  <p>Align Center Y to: <strong>Superview</strong></p>
  
  <p>Top Space to: <strong>Top Layout Guide</strong></p>
  
  <p>Bottom Space to: <strong>Bottom Layout Guide</strong></p>
  
  <p>And I have the <strong>Width and Horizontal Position Are Ambiguous</strong> message. I am trying to correct it, but I am not sure about what is happening in the first place. </p>
  
  <p>Do you have an idea?</p>