I’ve tested three different versions of the game - the last modded version of 0.3 from this thread, the 4.0.0-alpha.21 version from the releases section, and a bleeding-edge version built from the most recent git pushes. Aside from the fact that they all needed separate webgl resource packs, and would give version mismatch errors otherwise, they appeared to load, at least in the settings page.
The error you’re getting seems to imply that the browser isn’t finding the asset packs; there’d be some other error if it were a version mismatch or if your hardware or browser version didn’t properly support WebGL. If you’re 100% certain the image pack has been extracted to the proper place, make sure your local user account has permissions and ownership over the game directories and files. I’m guessing you’re not using a Flatpak-based browser or anything else that’s locked down or sandboxed more than usual, but if you are, make sure it has permissions for the game folder and subfolders. I’m also not certain how any of this pertains to you not being able to load images in other Twine-based games, as the embedded ones here seem to work and most Twine games also seem to embed their own images.