Now that we have a firm understanding of how theme icons work in jQuery UI, and we understand how icon sprites work within the framework, it's time to create some icons of our own.
As we've seen throughout the previous chapters in this book, the jQuery UI theme framework puts a large emphasis on providing a consistent look and feel. You can tell that two widgets, a date-picker and a progress bar for example, belong to the same theme. The same is true of theme icons in the framework. The same set of icons exists in all themes. When extending the theme icons, it is best to be conservative. Chances are there that there is an icon that can already represent what you're looking for. The "less is more" principle is especially fruitful when it comes to managing theme icons.
The examples in this section use the GIMP (GNU Image Manipulation Tool) for modifying the jQuery UI icon sprites. GIMP is freely available at http://www.gimp.org/ and runs on all major operating systems. Although...