Greetings, mod's author --
I was having questions about the whooping 400.66 MB file size for a portraits mod -- then I DL-ed it, and see why.
Firstly, those are some awesome work of arts there -- hats-off to the artist for that. 🍻
Second to follow is -- speaking as a fellow modder as well an end-user, I think ~400 MB for portraits mod is tad too large. I see here because they're scaled at 2K which is an overkill--portraits-wise--as they will be downscaled and fixed at around x256 in-game [at most], even when playing at 4K [IIRC]. I suggest you to scale them down to around x256 -- it's going to be fine. If you're hesitant on loosing fine details then you can go for x512 or even 1K if you're feeling it, but 2K's just too much.
Nonetheless, appreciate your work on setting up this mod. 👍
Much thanks for considering this -- cheers.
P.S. Considering using [uncompressed with mipmap 0 on the TXI] TPC format will be much appreciated as well [though not required] as it'd provide better performance with minimal-to-none loss of quality. If you're up for it, tga2tpc is the needed tool.