Someone on IRC was wanting to do an overwrite of the space background images used in the standard and maximum graphicsQuality setting. I gave it a shot myself, and couldn’t get the replacement graphics to take hold. The only thing I can think of is that it’s basically the same bug as http://ministry.kronosaur.com/record.hexm?id=1891, but with a different library (GalaxyLibrary.xml in this case).
Maybe have the engine force all of the stuff in Transcendence.tdb and the Collections directory to load before it parses anything from the Extensions directory?
If you get a chance, please attach the mod that you used for testing. I believe one problem is that the engine caches the image early in the load process [but I'm not sure].
Mod attached. (The idea had been to replace the space backgrounds with blank images to restore the old layered starfield effect without losing the other newly implemented effects.)
This also affects SM&M++ (including the demo version), where the override of the Kronosaurus' image gets nope'd by the engine.