I've been using GIMP now for years.
I'm still on the legacy 2.10 since I wasn't too happy with the interface in the new 3.0 version.
It has a built-in dds capability.
From the info on the GIMP site, the new 3.0 version should be fine with Win-11.
Like I said, I just didn't like the way the 3.0 looked.
"Old Dog," used to his "old ways" I guess.
ElCid97