Since 3.3.2 we have a feature that preloads all webp and gif files used by mods, and all these processes are done at the beginning of the reload.

The problem is that if a mod has lots of these files, this could lead to a big lag spike when the user presses F3+T before the reload screen appears.

It's not a big deal, but still pretty annoying. So my thought is to make the preload happen during the reload progress (and it would be better if we could reduce the lag) so that it doesn't block when someone decides to reload resources in the game.

It shouldn't be blocking. It's a problem if it's blocking!