People will cache this 8M file to their harddrives but everyone who visits this thread will be downloading it from NASA's website courtesy of this "IMG SRC" (and some may DL it several times if they are clearing cache).
Maybe it's a drop in the bucket but all those NASA downloads use their bandwidth (and also right now there may be many people trying to download this picture).
Gotta get my money's worth out of NASA any way I can.