If one clicks the "Download Image" button on the gallery slideshow, the photo can be seen full size by clicking on it. This can make a photo' that doesn't look much, eg. distant subjects, become more intresting. Also, another photo, whose thumbnail looks good, may be full of noise when seen full size.
By doing this you get a better judgement of the overall picture.
Perhaps the button could be renamed "View Full Size". After all you don't need to download it.
Thanx, bungiboy.