how to remove background image and get fore image

Question

there are two images

alt text http://bbs.shoucangshidai.com/attachments/month_1001/1001211535bd7a644e95187acd.jpg alt text http://bbs.shoucangshidai.com/attachments/

Answer 1

Instead of a straight subtraction, you could step through both images, pixel by pixel, and only "subtract" the pixels which are exactly the same. That of course won't account for minor variances in colors, though.