Personalizing your Today screen by replacing Microsoft's standard wallpaper and background with a picture of your choice is simple.
If the photo you want to use is on your PC, connect your Pocket PC to your computer and launch ActiveSync.
Click on the Explore icon in the ActiveSync window and then drag the photo you want to use from your desktop into the My Pictures folder on your mobile device. (Acceptable file formats are .gif, .jpg, or .bmp.)
Once the file is copied to your device, use File Manager to locate it, then double-tap the image file to open it.
Tap Menu and select "Set as Today Background." You'll be presented with the option to set the display area and the amount of transparency.
When you're ready, click OK and your new wall paper will automatically be saved.