After some recent discussion in the Mod Authors server, I had an idea. Perhaps mod authors could be presented with two options:
Lossy-compressed Images, which load with the page
Losslessly-compressed images, which load in the background after the page is loaded
Introducing author control would allow a mod author to individually control the user experience of their mod page, just as their own mods. But, how exactly would these two options work from a technical perspective?
There's a lot of talk about how to do lazy-loading for images. My suggestion for Nexus would be to serve small thumbnails for the image carousels (as you already do!) and, for the lossless images, defer loading them until a few seconds after the main JS executes. I would suggest using <link rel="preload" href="..." /> to perhaps load the lossless images early, but this might adversely affect users' internet data limits. Maybe you could defer loading lossless images until after the user opens the image browser—loading as many lossless images as possible once they open it.
However this is implemented, though, I would love to see this tradeoff given to authors. For things like texture overhauls, the compression artifacts in an image can make or break the selling point of the mod.