For gallery layout you can use set of settings to combine general amount of the thumbnails columns and how much columns every gallery image gonna take. When you open gallery settings in general settings block you can fine place where you can define column amount for the front end gallery layout. In settings possible to define different columns for devices with different screen size.
Another important option it’s amount of the columns which you can define in image settings section. You can define amount of the columns which every image gonna take.
With combination of this settings possible create absolutely different gallery layouts.
