Disabling of the zoom button in the lightbox if image is too large for the screen

Hello

It would be nice if there is an option to disable the enlarge function for images which are too large for the screen and therefore are automatically scaled down. It is very cool that lightbox scales the images down to fit them on the screen but why should we want to see full size image? I disabled until now the button by css:
#lightbox a#bottomNavZoom {display:none !important;}
but Im not sure weather this is the best way.