Note that with the current patch, images that are also links are not working (i.e. clicking on them loads the image but doesn't follow the link). I understand that left-clicking to load an image is quite handy. Now, FLTK2 has a nice feature with popups and it's that they can remember a menuitem position. If we make the right click popup remember the "load image" item, the same easeness of user interface may be attained (you may look in the test/menu program inside fltk2 sources).
Oops! Images that are links work in my personal tree, but I overlooked in when making the patch... The first click loads the image, and subsequent ones follow the link. Are you saying that you would prefer that it be moved to the menu anyway? I've been using left click to load for years now, and I would find it significantly less convenient to use the menu for every image...