title: iOS tab bar icons are blurry
body: <p>My tab bar icons appear blurry.</p>
  
  <p><a href="https://i.stack.imgur.com/fDRN7.png" rel="noreferrer"><img src="https://i.stack.imgur.com/fDRN7.png" alt="enter image description here"></a></p>
  
  <p>I created the icons using Photoshop, and followed the iOS Human Interface Guidelines when I  decided the sizes of each icons.</p>
  
  <p>e.g. icon size: 30x30px png</p>
  
  <p>This only happens with the tab bar. I wonder if this happens because of the resolution of the images or because of programming issues...</p>