what format to save terrain textures ?

hello,

i am currently replacing the terrain textures with newer and high quality once, but i am not sure which format i have to save them. the textures are located in common_client/terrain/textures/detail

i have read this theard: http://www.realitymod.com/forum/f189...explained.html

but no words about terrain textures

anyone can tell me which DDS format i should use ?