chamfered edges with photos

i am working on a website at the moment, which consists of alot of pictures. i have cropped all the pictures down to the size i want, but i would like to give the photos chamfered edges so the corners are "rounded"...does anyone know of any free or open source software capable of doing this...or how to achieve it in photoshop cs...?

found this site with a tutorial on the effect i am looking for...

http://paininthetech.com/using_paths_to_create_smooth_rounded_corners_in_photoshop

tried it and i seem to have a problem getting the image with just the chamfered edges to save. i can get the effect in photoshop but when i paste it to a new document and save the new document, the chamfered edges disapear