Thread:LOTRMod/@comment-26767096-20170228190157/@comment-25101089-20170304005238

Yes. For the purposes of biome generation, storing an array of IDs is quicker than just keeping the image and performing the biome-lookup-based-on-RGB-code every time, and it also uses less memory, since each ID is only a byte (0-255) but each RGB code is 4 bytes.