aiight i use psp for all my sigs, so i know how to this pretty fast and quick...
1- find the bg you want and put it in psp
2- goto layers-new layer, create the layer and put the pic of eminem on it
3- then use the lasso tool to cut out everything besides the part you want on your sig, and press delete once selected - make sure its on "replace" mode in lasso
heres an example of how my sigs look in psp with layers and all
have fun