title: What should image sizes be at @1x, @2x and @3x in Xcode?
body: <p>For example, I have a <code>100*100</code> size imageview or button, and I want to set its image or <code>backgroundImage</code> with a local <code>.png</code> file. Based on my understanding, I need to create 3 sets of images, i.e. <code>100*100</code> for <code>@1x</code>, <code>200*200</code> for <code>@2x</code>, <code>300*300</code> for <code>@3x</code>. I am not sure if my understanding is correct or not, can anyone help? </p>