Sometimes it is honestly easier to google up something than dig around in all of this
there's nothing "honest" about getting images that way!
Manic, my magic Princess is gonna pop out here and bonk you on the head!
Guess this needs to be said for noobs every so often...
web search engines (i.e. Google) are NOT free to use image catalogs. They're a good place to look for ideas, but not for externals - unless you add "royalty free images / free to use images" to your search.
There are lots of royalty free, ok to use on commercial sites, art websites. If you see a neat graphic on someone else's site - look for the copyright ASK them if you could use their image. Not all art has © copyright info on them, and if it doesn't have that, that does not mean it's ok to use it... it still has a copyright on it.
Try these places for free to sign up accounts, free to use photos. A few places will ask for credit on your image - just put it in your author notes. Showing your external links helps people know what work is your own and just how much work you did.
Stock.xchg (my favorite) has a great search engine - very fast and lots of great photos - they're very large too! Just read their usage rules. A few of the photographers would like you to email them what you've done with their art so they can see. When giving credit, give the photo number and website address.
I asked the owner of this site, if we artists at PSC could use their art on PSC, a commercial website. He said "sure! just give us credit and add a link to the site." Just list the photo, © Copyright 2007 [name of photographer], FreeLargePhotos.com.
They would like credit to the site and/or photographer. If you don't have a way to include the credit, that does NOT prohibit you from using the images.
All photos on this web site are public domain. You may use these images for any purpose, including commercial. But if some photo contains logos and products you need to be careful. Using someone else's trademark commercially can get you sued. Ex: photo where a CocaCola logo is in the background, do something to it - blur it or scramble the letters or just remove it.
The images and photos found in this archive come from three main sources: NASA, the National Oceanic and Atmospheric Admin., and the U.S. Fish and Wildlife Service. Each of these sites clearly state that their photos and images are in the public domain and give the conditions for their use. Please read their statements.
free stock photo site, Creative Commons licence, but don't forget to link credit back to FreePhotoBank.org