How are you resizing your pics in Photoshop?
If you scan your cels, they should all be 
roughly the same size. Then in Photoshop, just 
go to Image > Image Size > Change Width and 
Height to Percent and make them about 25% as big 
as the original. Save them with a different 
name, like "cel1prev," "cel2prev" etc etc and 
bang, you have your thumbnails. Just have those 
link to your full size pics and you're done.