what that does is makes it so when ever anyone clicks on a page that has that code showing the piture, imgred servers view the picture, cache it on their servers, then continue to serve it from then on out. [well for a while, but from what i can tell, if the picture has been cleared from their cache, the link will refresh if the picture is still at the original address.] its free. sorry let me try that again its free and there is nothing more to it than putting a little extra in the address to the picture. hell it will even do thumbnails if you want to view something along that line instead. [check out their website for the explanation on that.]
so go ahead have fun, it will make the internet a little easier to manage when it comes to picture placement in blogs/forums.