I need blog help!

I was wanting to make a new header for my blog. I just can not stay content! However, I have a problem. I completely forgot how on Earth to do it! What I am having a problem with is how to get the pics in a frame-type picture (like my header above). If any of y'all devoted readers know how to do that, please let me know or send me a link with a dummy version how-to list. I'd sure appreciate it! ;) Thank you!!