A Feature request seems reasonable, and somewhat oddly I don’t see one (in spite of support requests). Between requests and issues, there’s an enormous backlog, but sometimes extra volunteers will pop up.
Is it possible to set a date limit?
Filter question
How to backup files older than X days
Age direction varies. The one just above wants old files, but others (and you) want new, but idea is similar.
Support pluggable filter addons to ease implementation of special filtering is for a user- extensible system. There were some pretty specialized other ones I saw (but won’t cite) that I admit make this idea attractive. Still, for something that’s more common and possibly easier to extend the core with, dates seem a start…
A technical question which probably doesn’t affect backup of images is effects on deduplication when that file ages out, then someone modifies it, e.g. by appending some text. Normally only changes get uploaded per the block-based deduplication that backup does, but file churn (age away, come back) may interfere…