Image Resources
Morgue File Stock - Free
Stock Xchng - Free (use Advanced Search, and choose "restrictions OK > NO")
Flickr - Free (scroll down and check the boxes for Creative Commons licensing, for commercial use
iStockPhoto - $3 to $10+ - this is my favorite place to get (legal) images of people. You can also post an image request, asking if a photographer can take a specific shot for you.
Dreamstime - $1 to $4 - not as easy to use as iStockPhoto, but it is sometimes cheaper.
CanStockPhoto - another good paid site, decent selection of Jewish images
USDA Image Sources - Free
Agricultural Images - Free
Gimp-Savvy Repository (NASA and other sources) - Free
I hope I was of some help. Please feel free to contact me if you need any design advice or are looking for resources. (Yes, even if you are looking to go into this field- there are plenty of Shluchim jobs to go around.)