Create your own Theme for Windows 7....

While on the subject of Themes, maybe you'd like to make your own. It's easy. Just pick out several of your favourite pictures for backgrounds, and then resize them to match your desktop's native resolution. Mine's 1680 by 1050, but yours may be different. Once you have them the right size, create a new folder named DesktopBackground (all one word) and put them in it. Number them consecutively in the order you'd like them to be when displayed. Now, put that folder named DesktopBackground into another you create named for your new theme. Put your newly-named theme's folder into your Username\AppData\Local\Microsoft\Windows\Themes folder. Now, open your new theme's DesktopBackground folder, and then click on 'Select all', and then click on any one of those and select 'Set as desktop background'. This will start your new theme on the Desktop. After it starts, you can go back to your Desktop, and right-click to get the menu from which to choose Personalize and then you can click on the 'Desktop Background' along the bottom of the window, and set the timing for how often it changes pictures, and whether to have them Shuffle, which is a random choice, or not. And that's it - your new theme is working. You can change to or from it just like the others, by going back into "Personalize" from the Desktop. When it first shows there under "My Themes", it will be shown as 'unsaved theme'. Right-click on it to get a little menu on which to choose 'Save', and then fill in its name. It will then be a  permanent part of your themes.

This is an example of a homemade theme in Windows 7, made up of a series of pictures of clouds that I took last summer. One thing to remember about making themes for your monitor's background is that you probably don't want them too distracting, so something like these clouds works out quite well. But do your own thing, and have fun with it.