What kind of amateur pictures are these? Remember that none can allow you expose him/her on the net. Be carefull. You can post, sell, use in any possible way your own pictures. Would you allow anyone else to use your pictures?
Some times amateur pictures are not so "amateur" . Are made to seem like amateur for promotional tactics. If you want to offer , or sell, pictures in your site you can easilly buy from studios for about 10 USD. take a look:
http://www.adultcontent.co.uk/main.phtml
http://www.amaphotocontent.com/homepage.php
http://www.cool-content.com/default.aspx
These are some of them. Search by keyword " Adult content" and you 'll find a handfull of studios. A very good place to find content for your site is GFY forums.
Post a message ( thread) and you'll see.