Yup, use shortcut command shift 3 or command shift 4.. These are very handy in that the former will let you print the screen and the latter will let you specify what area of the screen you want to frame!!
I believe the OP is referring to iChat > iChat menu > Change My Picture - clicking the Camera button in that dialog box snaps an image with the iSight. It does not save the image to Photos, within the iChat package, in Application Support, or anywhere obvious to me from a cursory look.