So I had assumed files in gfx/env/skyname.tga were automatic downloads and that's why they weren't generated by resGen.
But then I found out clients were only seeing default skys.
So I added them to the res file. But they still weren't getting them.
I had to gather the files and send them directly to client.
Only then could they see the sky intended for the map.
So what am I doing wrong?