SSE What program to use to make heightmaps for SE?

[HappySlapp]

I use World Machine to make the map, and I lowered the brightness levels of the exported 16-bit .png in gimp and then exported to .raw (using 16-bit depth) and I ran it through TESAnnwyn, but everytime it's either flat, or like the Far Lands from Minecraft... I'm completely stumped.

[esuriddick]

I don't usually work with textures, but I believe that in the past, after creating the map I would, simply make it in GIMP and then convert it to DDS following Skyrim's settings (also within GIMP).