Move docs to 09

Author: BentiGorlich

…ptional-features/08-image-compression.md …ptional-features/09-image-compression.mddocs/02-admin/03-optional-features/08-image-compression.md renamed to docs/02-admin/03-optional-features/09-image-compression.md docs/02-admin/03-optional-features/08-image-compression.md renamed to docs/02-admin/03-optional-features/09-image-compression.md

@@ -12,4 +12,4 @@ Like setting-up:
 - [S3 storage](06-s3_storage.md) - Configure an object storage service (S3) compatible bucket for storing images.
 - [Anubis](07-anubis.md) - A service for weighing the incoming requests and may present them with a proof-of-work challenge. It is useful if your instance gets hit a lot of bot traffic that you're tired of filtering through
 - [Monitoring](08-monitoring.md) - Internal monitoring of requests and messengers
-- [Image compression](08-image-compression.md) - compress images if they exceed your maximum image size
+- [Image compression](09-image-compression.md) - compress images if they exceed your maximum image size