I would like to store images and configuration data on a device in a persistent manor.

Previously I have seen LocalStorage and IndexedDB being inexplicably wiped so I don't trust them as persistent, perhaps more like long term temporary storage.

I also can't really store images there without converting the images to base64 and storing them as text, which is a little cumbersome.

I would like the user to be prompted that my web app would like to access the filesystem so they are cognizant of that, but I would not like to have access to everything and I would like the prompt to appear once on first launch.

I am reading through the FileSystem API and it looks like there might be a solution there but I haven't found it yet.

Any suggestions to point me in the right direction?