Remake PR #23567: CompressedImageSaver revamp

>for now I have merged the textures into this branch, but before merging we should place them in the bevy asset repo

I think this is merged too quickly. The assets have not moved to bevy asset repo. Even if we delete these files later, the git history is permanently bloated unless you force push to rewrite history.

_Originally posted by @beicause in https://github.com/bevyengine/bevy/issues/23567#issuecomment-4368441340_

This PR was force-reverted due to the accidental inclusion of large asset files. @mockersf also reports that it broke (or at least changed) parallax mapping: https://discord.com/channels/691052431525675048/1500880505959092345/1500969107078778960

The issue describes remaking the CompressedImageSaver work after a force-revert. Start by reviewing PR #23567 and the linked discussion, then identify how the textures should be moved to the Bevy asset repository and whether parallax mapping behavior changed. Done means the large assets are no longer included in Bevy history and the reported mapping behavior is addressed.

Written by the indexing model from the issue text.