Here you can by Pixel Space by a size of 10 x 10 Pixel. 1 Pixel = 1 Dollar. A Pixelblock will cost 100 $.
You can upload images at the size of the blocks you bought and place backlinks to your website. The backlinks are search engine friendly and placed for lifetime.
You can also ask for Link Exchange.
The Pixel Grid
Login or register on top of the page to buy pixel blocks for backlinks.