1. A system comprising: one or more processors; and one or more computer-readable storage media storing instructions that are executable by the one or more processors to perform operations including: detecting that new tile content for a tile is received that exceeds available storage in an existing tile slot for the tile; storing the new tile content in a new tile slot in a cache; mapping the tile to the new tile slot; and reordering the cache to incorporate the new tile slot such that a tile slot order in the cache matches a visual order of a group of tiles that includes the tile.