 <p>You should look into the UIAppearance proxy in iOS 5. For earlier versions the singleton approach seems fine, you request an appearance change to the singleton which changes its various images, then either sends a notification (NSNotification) to inform any interested parties who would want to update their interface accordingly. Or you can set key value observers (KVO) on the singleton properties so they are automatically informed when one of them changes.</p> <p><a href="http://stackoverflow.com/questions/145154/what-does-your-objective-c-singleton-look-like">This post</a> shows you how to implement a singleton. It's just a way to be able to access the same instance of a class from anywhere. <a href="http://www.makebetterthings.com/blogs/iphone/singleton-design-pattern-for-objective-c/" rel="nofollow">Here</a> is a link to a discussion about the singleton design pattern along with a more involved "pure" singleton implementation.</p>