How to view a picture in gallery without seeing other pictures tiled at the bottom

My s7 is now showing multiple pictures (in form of tiles) at the bottom of my screen when I'm viewing a picture in my gallery. It is especially annoying if I hold my phone in landscape orientation as those pictures at the bottom overlay part of the main picture I'm looking at. How do I set it so I don't see those pictures at the bottom when viewing a photo in my gallery? It did not originally do this, but now it is and I'm not sure how to change it back.

If you don't want to see the thumbnails, then just tap once on the photo and they'll disappear, tap again and they'll reappear so you can navigate to photos quicker.