Before starting

First of all, create a folder with any name, adding at the end the extension ".theme" and place it in the path /Library/Themes of your device.

Themes are organized in folders and they consist in changing images.

A very important thing is the distinction between devices. From now, iPod touch and iPhone will be named as iPhone and iPad as iPad.

The name of the images of iPhone or iPad and iPhone or iPad with retina display are always the same but you have to add the suffix "@2x" for the iPhone with retina display (e.g.: icon.png -> icon@2x.png and icon~iphone.png -> icon@2x~iphone.png). About the size, the images of the device with retina display are usually double sized than the images of the iPhone and the size of the images of the iPad, compared to the iPhone, it depends.

In the iPhone or iPad with retina display, you may need to include the image for the iPhone or iPad without retina display in order to change the image for the iPhone or iPad with retina display.

When the name of an image is given, in brackets will appear the name as it's called in the iPad.

The structure of the retina display images that end with ~iphone is @2x~iphone (for the iPad is the same but with ~ipad).

The folders called "Bundles" and "Folders go in the main folder of the theme.