Picture Effects

[pb100191]

I have a website on pizco.com and i'd like to know;

I have several pictures, and i would like to know how to combine them so they all fit together as one picture. I don't mean as in how you can do it in paint etc, i mean it generally overlaps each other...anyone understand?!
It might be to do with photobucket or something - but i doubt it. It's a pic effect i guess....