Hi araxis,
Yes, you need 2257 docs for any image you use on your pages. You can't just grab content from the internet, it's against the law.
There are a couple ways to get content, you can use sponsor free hosted content, which most sponsors offer when you sign up as an affiliate to promote them.
You can buy content from a content provider (like me) When you buy content, it can be used to promote any sponsor, or build a paysite, whatever you want to use it for. Each content provider has their own terms of use, which you should read. Here's our license,
http://www.midnightdigital.com/license.html
If you can't afford to buy your own content right now, I may be able to help you with that. We give a set out free complete with all 2257 docs for signing up for our mailing list. Go here
http://www.midnightdigital.com/main.html and on the bottom of the left menu you'll see where to sign up. Your set will be sent to you by e-mail.
Hope this answers your questions
