My nice Canon scanner stopped working with our iMac when we upgraded to OS X 10.7. Apple changed their scanner driver architecture, and Canon didn't revise the old drivers to work in the new framework. So, I got a USB 2.0 card for my old Mirrored Drive Door PowerMac G4, which only runs Mac OS X up to 10.5.8. I installed the latest Canon drivers, and started scanning away.
I noticed one oddity, however. With the latest Canon driver (10.2.4.1X), the CanonScan Toolbox application works fine. However, if I try to use Apple's Image Capture application, there are problems. The preview scan shows the entire document, and I can select the entire document, but when I scan it to PDF, something cuts off about an inch from the top of the document. Bummer.
Everything works fine when scanning with Apple's Preview application. Very odd, as both applications appear to use the same scanner software component.
I didn't see anything on Google about this bug, so I thought I'd mention it here.
Update:
I haven't confirmed this thoroughly, but it seems this bug is triggered by manually inputing the image size in text boxes right-hand side of the dialog box. If I instead set the image size by dragging the rectangle in the preview in the left-hand side of the dialog box, Image Capture operates correctly and does not cut off the top of the image.
Also, I've reproduced the bug using the Preview application's File->Import Image... menu item, so it does exist in both applications: Preview and Image Capture.