While you can suffer from "Image Persistance" on LCDs, it is generally more rare and takes allot more to cause it. It also can in general terms be corrected. Everyone is more used to the term "Burn In" concerning CRT's, where it is a real concern, this same problem applies to Plasma tv sets.
As far as LCD's go: try these items if you have any IP:
- Turn off the monitor for extended periods of time. It can be as little as several hours or it could be as long as several days.
- Use a screen saver with a rotating image and run it for extended periods of time. The rotating color palette should help remove the persistent image but it could take a long time.
- Run the screen with a single solid color or bright white for an extended period of time. This will cause all of the crystals to be reset at a single color setting and should hopefully erase any previous image persistence.