Very easy actually. You need:

-A hard drive or a USB (If you use your hard drive you will need a transfer cable)
-Modio or Horizon
-Pictures

USB Tutorial: http://www.youtube.com/watch?v=Z79-OiTjDdY
Hard Drive Tutorial: http://www.youtube.com/watch?v=c_FVqZr2mWU

If you don't understand how to do it with these videos I can explain if you like. I'm used to the modding tools and such since I've been doing it for god only knows how long.