title: iOS: display an image with the same quality for all screens
body: <p>My view in the storyboard contains an imageView having for the constraints top= 0, height= 55, width= 230 and centred horizontally. Using the "view as" option in the last version of Xcode, I realise that the display of the image and its quality are not the same for all the screens. In the iPhone 4s the quality is good but the image same big. Otherwise, in the iPhone 6s plus screen, I see that the image size is good for the screen but the quality isn't well.</p>
  
  <p>How the image can be displayed the same way in all the screens? Can anyone please give me the right constraints to resolve this?</p>