optimize refresh image preview

[wu4339]

Each open there is a refresh image preview of the process, whether it can be optimized, so that the experience will be better

[hardcore-sushi]

Yes it's already planned: TODO.md

[learnmlcolab]

@hardcore-sushi I saw a comment from you here.

Storing them encrypted in a hidden folder in the volume would modify the volume without the user's decision, which is not what we want.

Would you consider this option? I'm thinking the app could ask the user for permission to store thumbnails in a .thumbnails folder at the root of the volume or something like that.

Currently, I'm having a volume with a large amount of images and videos, they all have default names from the camera app so it's hard to know which one to open without thumbnails, and it's not practical to wait for thumbnails to load each time, especially for the videos.