The best way is that you look for images that touch on subjects you like, Or create your own (If you happen to draw.) Ways to find great images that appeal to you;
Image Sharing - MPGH - MultiPlayer Game Hacking
Also;
deviantART: where ART meets application!
When using dA Please be aware that the user must allow people to use their images without credits, or provide credits for their dedication.
If you can not find anything still (Which I doubt will happen
) You can always contact me about creating a drawing.