I have seen in the apple site their big-images gallery in this link (for example):
What attracted my eyes was that they sort-of masked these images so they will not be displayed outside the gallery box. In flash/as3 it is quite simple to mask an object - but how did they do it in the web?
How does it work?
Well it's often done by making the image the background of a div. This div has hidden overflow, and the background image is centered in it. Within the div theres a img element which is a transparant png that can be used as the mask.