After a long time being switched off, I've fired up the trusty Epson Perfection 610 to scan a mail Proof of Posting to send to someone who thinks I haven't mailed their item.
Any hoo - all I'm getting is this:




So I tried rotating the image and got this:



I've tried adjusting numerous settings, and saving to different file formats - nothing's actually helping.
I can't scan it using TWAIN acquire and Epson's own software since I'm on Snow Leopard, and it's (I believe) EOL now. It's just an extension to Image Capture (which whilst it has some good points, is nowhere as comprehensive as the Epson Scan software was).

Bit annoying, as I know I've scanned images on this very machine, with that very scanner.

Any clues?

We had something similar on our Microtek scanner at work - the drive belt that moves the scanning lamp up and down was slipping. Try opening the lid and doing a test scanner to make sure the lamp is actually moving as it should do.

Just did a scan with the hood up to watch the lamp's progress with the first thing that came to hand - it was fine! Scan was great!
Closed lid to do a scan with the actual thing I want to scan in place... and we're back to the usual wobbly mess.

Most odd.

Gremlins?

Maybe this plugin to Image Capture has become corrupted in some way, perhaps if you can find the relevant preference (.plist) file to trash it in Home > Library > Preferences

If you don't know what the preference file is called, try logging into another user account and try it in there - scanning in a new (virgin) user account should reset it.

Have you checked out VueScan - according to their list of supported scanners, the Epson Perfection 610 is supported.