have you considered getting a different gallery viewer? the current one's a bit annoying cause you have to scroll down each time you click next (if you're on a laptop) to view the pic. i usually don't end up looking at every pic 'cause this gets annoying after a while.
how 'bout a viewer that "pops up" and automatically resizes to fit your screen up to the image's max width/height.
click on the first pic, which is landscape (horizontal). click "next" and you'll be able to see the next image w/o having to scroll...the viewer just resizes if it needs to, which in this case it does 'cause the next image is a portrait (vertical). if your screen is small, it will resize to fit that screen, but you still have the option to see it at full-res as you'll see a magnifying pointer if you move the mouse to the center of the image.
i hope all that made sense.