It's now time for us to create new icons for our theme. The first step is to update the sprite image files. The second step is to add new icon classes to the theme CSS.
For this example, I'm adding one new icon to my theme. I need a new simple shape - a diamond. This new icon is illustrated as follows:
You can use any image you like for this example. The only restrictions are that the image needs have a dimension of 16x16 pixels: