Currently AI generated images aren't stored on Kagi servers, meaning once the image generator provider removes the image, it's also gone in the Assistant.
I think it makes sense to store all generated images on Kagi servers (as users who requested to generated them, paid for it).
Probably makes sense to then just give them a lifetime for the lifetime of the thread.
By default this would mean that the images get deleted after 24h assuming the user kept their thread lifetime setting to the default 24h. But if a user has it set to forever.. then maybe keep the image for a month or 6 maybe? (or the entire thread lifetime, is financially possible I guess)
And if the user marks a thread as 'preserve' then it keeps it for the entire duration of the lifetime of the thread
