Why start with images divisible by 60 pixels? Although MTM2 and 4x4evo terrain textures are 64 by 64 pixels in size the real core of the texture is the 60x60 pixel central area. The two pixel border surrounding that core is actually just a repeat of the leading edge of the adjacent texture, meant for "overlap" as the terrain is rendered in the game. You must therefore create your terrain textures as a composite image based on 60 pixel increments and feed it to Slice60 for the necessary edge processing. If the edges are not processed properly the resulting tiles will not be "seamless" in the games.

For more information, please see : [ 1 ] [ 2 ] [ 3 ].