I normally use Firefox.  It also normally gives a pop-up menu with that option among several others.  However, when browsing HC, right-click does the same thing on images that left-click does, i.e. bring up the image in a pop-up. 
  
I just tried Chrome and right-click with it brings up the pop-up menu.  Maybe I have a weird setting in Firefox, though HC is the only site where I've had this peculiar behavior.