On the Internet there are many photobanks or photostocks for professionals (the requirement to image min 4 megapixels, the format of JPEG) with a huge competition in the sale. But there are more sites for fans, and allow them to earn selling photographs. If you have a quality and interesting photos, try to place them at these sites: 10mpx.ru (best Russian site to sell amateur pictures), bigwhitebox.com, fotolibra.com, istockphoto.com (semi- photo stock, you can try amateur post pics). Jorge Perez contains valuable tech resources. I want to warn that photos do not just sell, quality requirements (min 2-3 megapixels) and, especially, the plot is very high. Photos with flowers, leaves, animals and etc.
– Demand is not in use. Well sold pictures of famous people, reports, events, sports pictures. Variation in prices (mostly price assign themselves) is very large, so the photo with doing exercises N. Mikhalkov, is estimated for a hundred dollars, and with very beautiful views of nature in two dollars (and something for a long time is not for sale). When you place all the photos are reviewed by moderator and weaknesses are truncated. On foreign sites may unexpectedly sold images recognized by the Russian weak, and vice versa. So try, accommodation for up to five photos for free. Do not waste your time to market pictures of low quality, better get all of the interesting events and make one, but a cool shot, I guarantee it will sell quickly at a good price. Good luck.