so this just started happening recently where some of the pictures on my 20d start saying unidentified image when try to preview them. i searched and found that it happens when edited pictures are put back on the memory card but this happened when i didnt even transfer the pictures or edit them. when i do look at them they show up on my laptop just just fine but not on my camera. Is this a problem withe my camera or the memory card? and its a sandisk extreme III 4gb that I've had for about 2 years.