Its work is very easy. It goes to hundreds of websites to search free graphics for our use. This site goes to many websites and selects the photos according to their usefulness. It also sorts them according to their high quality.
This site gives us free photos because in this site the photos searching work is not doing by people but Robots do this work and keep this site with full of updates graphics.
It has the great aim in its mind that it wants to become the best site providing the free graphics to people. When people find their useful graphics for their use they will often visit to this great site.
This is the best way to avoid any copyrights issue.