When putting a map into the item frame usually you can piece together a huge map of your world by using multiple maps. Every time you go off of one map open a new one. When putting them into the item frames mounted on a wall the maps glitch out. It's strange. The glitch: say you have map #1 in an item frame. You place map#2 in an item frame next to it expecting to make them look linked seamlessly. Unfortunately for me they both look like map #1. When I added a few more they started jumping through the #'s showing duplicates in the different item frames where I placed different numbered maps.