In Photography version 1.5+ we have added new gallery, gallery archive and portfolio template layout name “Mixed Masonry”. For customers who updated from previous version will have layout issue.
It’s easily solved by installing “Regenerate Thumbnails” plugin and run the plugin once you installed it. It should re created all images in your WordPress media library and the new layout should be displayed correctly.
Note: Please make sure you upload image which is large than 1024×768 px so this mixed masonry layout can displays properly.