I'm running Windows 2000 on an older computer. I'm getting these artifacts on images (see attached). It only occurs on JPEGs, nowhere else. It does *not* occur on screen, or even in GIFs. They are randomly appearing - simply refreshing my browser is enough to get a different arrangement. But scrolling the screen does not alter them (eg. if I scroll a JPEG off-screen and back on, the artifacts act as if they are part of the image, remaining in-place.) This is not a video card problem, as I have just replaced that. Ever seen such a thing? Some sort of JPEG display malfunction?