To create modern image and video galleries, J1 Theme implements the jQuery plugin JustifiedGallery. The module is a great tool to create responsive, infinite, and high quality justified image galleries.
Pictures you've made are typically not even in size. Images may have the same size (resolution), but some are orientated landscapes, or others may be portraits. For that reason, a more powerful gallery is needed to create so-called justified views. JustifiedGallery uses a so-called masonry grid layout. It works by placing elements in an optimal position based on available horizontal and vertical space. Sort of like mason fitting stones in a wall.