With additional effort you can by including the proper JS. However, many sites would find this a benefit rather than a problem, since hotlinking takes away page-views.
Re:BPG Image format
by xanderjanz on Friday December 05, 2014 @09:48PM
(#8708169)
You wouldn't really have to change the right click menu. You could put an invisible html div over top the images, and give them the correct link, instead of the raw decompressed image data. So a user would think they are right clicking the image, when really they are right clicking our overlay.
If only the rightclick menu could be customized by JS. Adding only a limited number of entries to the menu seems like it'd be okay.