Nearly all the chips at chipguide.com are scanned at 100 dpi, in a 158 x 158 pixel box. The chips usually run from 153 to 157 pixels in diameter, depending on the type of chip and the amount of wear. After scanning to a .tif file, I use Photoshop to remove the background and shadows with the circle tool, then I use the batch conversion tool in CompuPic Pro to convert them all to .jpg files. I save them at 80% which generally leaves me with a 10K to 20K file.

Greg