Well, U are theme developer, so its your decision, how will your theme show galleries.
@tajdik Actually, I just realized this is not a bug. In fact, the Independent Publisher theme and the TwentyFourteen theme behave exactly the same. The difference is that the TwentyFourteen theme has a smaller post width (
The maximize size of the thumbnails (in both TwentyFourteen and Independent Publisher) is
If you resize the browser window when testing the multiple gallery columns on Independent Publisher, you'll see the same effect as you have on TwentyForteen:
You can change the default thumbnail size from