QA what? You can’t QA and optimise huge ass textures to fit into a gig. I can tell you a story about high res images. My partner is a photographer. She did a commissioned project of 7 collage photos to be printed in large scale. She bought a 512 gig drive to work on a project. These 7 photos took 95% of the space of this drive in the end. Yeah, 500 gigs for 7 bloody photos!
They are collages, meaning that each PSD file contains multiple super high res photos. But the end result is just 7 huge pictures on the wall.
As for the final pixel size, I don’t remember now, but they’re over 100mpx of 32 bit per channel of image data (that’s 16 bytes per each pixel instead of regular 4).