ORIGINAL: junk2drive
The graphics that I used came out of the Mapmaker folders which came after Koios. I am pretty sure that they came from the internet and not drawn by an artist.
Do I need to do a .dds as well as a .png? If so, what output?
I think I ended up using only the PNG files to generate a texture with mip-maps and DX compression on the fly as the PNG files are loaded. If you've only modded the PNG files and got the snow to work, then that's what I did, and the DDS files are unused and unnecessary.
For snow, we should probably do new spec and normal maps too (snow has a lot of specularity), so maybe this is the sort of thing that ultimately we should try to do with a program like Filter Forge -- which can generate terrain textures and spit out spec and normal maps along with the diffuse maps. However, your screenshots look pretty darn good to me, so maybe we don't have to worry about the spec maps right now (I'm sure our artists would freak out if they heard me say "don't worry about the spec maps" [:)] )