docs: improve backup instructions; closes #1613

site/src/docs/backup/backup/index.md

@@ -18,3 +18,5 @@ This command creates `userbackup-{site ID}-{timestamp}.gz` file by default.
 ## Backup format
 
 The backup file is a text file with all exported comments separated by EOL. Each backup record is a valid JSON with all key/value unmarshaled from the `Comment` struct (see [here](https://remark42.com/docs/contributing/api/#commenting)).
+
+Avatars and images are stored separately. By default avatars are stored in `./var/avatars` and images in `./var/pictures` and need to be backed up, as well. For more information, check the [technical details of the backend documentation](https://remark42.com/docs/contributing/backend/#technical-details).

site/src/docs/contributing/backend/index.md

@@ -55,7 +55,7 @@ To run backend - `cd backend; go run app/main.go server --dbg --secret=12345 --u
 
 Data stored in [boltdb](https://github.com/etcd-io/bbolt) (embedded key/value database) files under `STORE_BOLT_PATH`. Each site is stored in a separate boltdb file.
 
-To migrate/move Remark42 to another host, boltdb files and avatars directory `AVATAR_FS_PATH` should be transferred. Optionally, boltdb can be used to store avatars as well.
+To migrate/move Remark42 to another host, these boltdb files must be transferred. Additionally, the avatars directory `AVATAR_FS_PATH` (default `./var/avatars`) and images directory `IMAGE_FS_PATH` (default `./var/pictures`) must be transferred. As an alternative to storing avatars and images in the file system, boltdb can be used by setting `AVATAR_TYPE` or `IMAGE_TYPE` to `bolt`. Files in the `IMAGE_FS_STAGING` directory can be safely ignored because they are moved to the image store between app restarts.
 
 The automatic backup process runs every 24h and exports all content in JSON-like format to `backup-remark-YYYYMMDD.gz`.