Is the image you're using as a background saved to your memory card? If so, every time you sync the background image will change. To stop this from happening, move the image to the device's internal memory (go the picture location on the media card, click the blackberry button and select move and move the picture to "Device Memory".
Is the image you're using as a background saved to your memory card? If so, every time you sync the background image will change. To stop this from happening, move the image to the device's internal memory (go the picture location on the media card, click the blackberry button and select move and move the picture to "Device Memory".
Mine was doing the same thing. I never did copy it to device memory and for whatever reason it stopped doing it. My only guess is that once I upgraded the device's OS to the latest release, it fixed the bug.
Worth a shot.
See the sticky at the top of the page on where to find and how to do the upgrade.