Tile sets should support something that's commonly referred to in the RPG Maker community as autotiles.
Auto tiles look like one tile in a sprite sheet, and you paint with it as if it's one tile, but it's auto calculations which tiles to place depending on their layout. Autotiles are for placement of things like repeating terrain, such as water, grass, and trees, that can have corners and edges.
Tile sets should support something that's commonly referred to in the RPG Maker community as autotiles.
Auto tiles look like one tile in a sprite sheet, and you paint with it as if it's one tile, but it's auto calculations which tiles to place depending on their layout. Autotiles are for placement of things like repeating terrain, such as water, grass, and trees, that can have corners and edges.