question

I don't think this has been posted before... I was wondering how I can get an effect like:

- by letsey_x ?????

I don't wanna know the coloring technique just how you blend 2 pictures like that. I've seen a few icons around LJ with this effect and I would like to try it on some of my icons, so if anyone knows how to achieve this I would greatly appreciate any and all help!!

Thanks!