TabBarItems and setting their image sizes?

You should prepare 3 images icons for each tab bar item (1x, 2x and 3x).

First create the 3x at 75w 75h pixels (maximum: 144 x 96) and save it as [email protected].

Then resize it to 50w 50h pixels (maximum: 96 x 64) and save it as [email protected].

Finally resize it to 25w 25h pixels (maximum: 48 x 32) and save it as iconTab0.png.

Now all you need is to select those 3 images at your finder and drag them to your image assets.

Human Interface Guidelines