I have a Canon 20D.
I have had it about three years.
Just within the past month, it developed an error in the image - in which, at least in the raw mode, appears as a row of pixels near the bottom of the image that are not written correctly.

This error looks different, depending on the viewer.

On the on-camera LCD, it appears as a pixel-wide horizontal line near the bottom of the image - but there are also very faint vertical lines arranged horizontally across the image - darker around where the thin horizontal image is.

Whe viewed on the canon digital Photo Professional application when downloaded on the computer, the error appears as the same thin, pixel-wide line near the bottom of the image - but also with a wide line of purple noise near the top of the image, as well as another thin purple, horizontal line near the top of the image. The faint purple vertical lines do not appear when viewed this way.

When the raw is converted into a JPEG, the image appears with a several-pixel wide horizontal line near the bottom of the image, but does not present the faint vertical purple lines and does not present the wide purple noise line near the top or the second thin purple line near the top.

I am wondering whether this is a sensor problem, a problem with the firmware that writes to the memory on the sensor, or a problem with the firmware that reads from the memory, or some other processing error.

It is interesting to me how different the same problem appears in each image - but there is a problem with every image, no matter how viewed.

Thanks for any insight or advice you might give as how to approach this problem.

Thanks