Well wat i do is copy and paste any of the terrain textures in the same folder and call it watever like sparkly grass, then open it up in GIMP, rub it all out and make my terrain look how i want it, then save it in the same folder as for example "sparklygrass.jpg" just remember to add .jpg to all of them, once saved i go onto FH, map maker, the world tab and find the "sparklygrass.jpg" texture. Thats how i make mine hope it helps and if its wat wanted.