title: screen resolution for android and iPhone design in Photoshop
body: <p>For iPhone an Android design,
  why we set the psd resolution up to 72? 
  why we aren't using 160 for mdpi and 240 for hdpi so on.
  And what are the difference in design android app or iPhone app more than 72 res?
  Just increase the file size and clarity? 
  Please let me know.</p>
  
  <p>Thanks,
  Arun.
  <img src="https://i.stack.imgur.com/S1Nub.png" alt="enter image description here"></p>