Yes, I sort of knew about that, but figured that only a very sharped-eyed visitor would notice it. And with the darker color schemes, it's almost invisible. To make maximum use of the screen real estate, the image padding is reduced to a maximum of 2px on a phone. But that padding is where the shadow is shown, so it "spills off" the right edge.

Your suggested fix is the correct one. The shadow is of little use on a tiny display.

Open the skin directory - Tools, Open directory, Skin directory - and replace the common.css file with the attached version, then make the album again. You might have to do some aggressive cache-clearing on your mobile device to see the change.