I agree with Andy's posting above but on my systems you only get the 'Download' option when your mouse hovers over the image within the Gallery albums.
However within a comment in one of the Discussion topics where an image has been uploaded and also where a comment has been made on an album image entry and a new image has been uploaded into the comment I don't get the Download option when selecting those images by a left click with my mouse.
My first click on the comments images gives me an enlarged image (50%) with the microscope tool (for enlarging the image to 100%).
I then left click with mouse and I get a new screen with the image and I have to right click with the mouse to get a set of options, including 'Save as' that I have to select and save (download to my downloads folder) with either the system image name or a name of my choice.