Clean up orphan images

README.md

@@ -92,6 +92,27 @@ Image URL inputs offer an **Upload image** button when all of these settings are
 of NSFW images. Set it to `false` to skip NSFW moderation and model initialization. Empty or
 unrecognized values keep checks enabled.
 
+The Debian package includes `reminder-rs-clean-images.timer`, an hourly cleanup job. Enable it
+after configuring S3 and starting the bot (which applies database migrations):
+
+```sh
+sudo systemctl enable --now reminder-rs-clean-images.timer
+```
+
+Each run records the first observed orphan time in `image_uploads.orphaned_at` (UTC). An upload
+is orphaned when neither a reminder (including archived reminders) nor a template uses its URL
+as an avatar, image, thumbnail, author icon or footer icon. Referenced uploads have this timestamp
+cleared. `IMAGE_UPLOAD_ORPHAN_RETENTION_SECONDS` controls the additional retention time after
+detection; it defaults to `604800` (seven days) and must be a positive integer. Unsaved uploads
+are also covered. Cleanup rechecks references before deleting and removes the tracking row only
+after S3 confirms deletion; failed deletions are retried on later runs. Each run attempts up to
+1,000 expired uploads from the configured public URL's `uploads/` prefix.
+
+For other deployments, schedule `/path/to/reminder-rs clean-images` hourly with cron, using the
+same working directory and configuration as the bot. The command requires no Discord token
+and skips NSFW model initialization. With no S3 settings it exits successfully without work;
+partial S3 settings or invalid retention values fail the job.
+
 ## Running with Docker
 
 ### RustFS for local development