Bitmap Pixel Collision?

I’ve found a couple of tutorials on this method of collision, it seems like a really useful method. However, I can’t find any implementation that doesn’t use examples of XML loading to a backbuffer. (This isin’t a bad idea, but I have no XML experience.)

I just can’t find an explination on how this works, the tutorials I’ve found are all sort of vague when it comes to if the collision is happening in flash or in the loaded backbuffer.

-Blackroot.