Add screenshot for backup warning, minor edits

ee/dtr/admin/disaster-recovery/create-a-backup.md

@@ -25,20 +25,20 @@ Docker Trusted Registry maintains data about:
 This data is persisted on the host running DTR, using named volumes.
 [Learn more about DTR named volumes](../../architecture.md).
 
-To perform a backup of a DTR node, run the `docker/dtr backup` command. This
+To perform a backup of a DTR node, run the [docker/dtr backup](/reference/dtr/2.6/cli/backup/) command. This
 command backups up the following data:
 
 | Data                               | Backed up | Description                                                    |
 |:-----------------------------------|:----------|:---------------------------------------------------------------|
 | Configurations                     | yes       | DTR settings                                                   |
-| Repository metadata                | yes       | Metadata like image architecture and size                      |
+| Repository metadata                | yes       | Metadata such as image architecture and size                      |
 | Access control to repos and images | yes       | Data about who has access to which images                      |
 | Notary data                        | yes       | Signatures and digests for images that are signed              |
 | Scan results                       | yes       | Information about vulnerabilities in your images               |
 | Certificates and keys              | yes       | TLS certificates and keys used by DTR                          |
 | Image content                      | no        | Needs to be backed up separately, depends on DTR configuration |
 | Users, orgs, teams                 | no        | Create a UCP backup to back up this data                        |
-| Vulnerability database             | no        | Can be re-downloaded after a restore                           |
+| Vulnerability database             | no        | Can be redownloaded after a restore                           |
 
 
 ## Back up DTR data
@@ -49,7 +49,9 @@ To create a backup of DTR you need to:
 2. Back up DTR metadata
 
 You should always create backups from the same DTR replica, to ensure a smoother
-restore.
+restore. If you have not previously performed a backup, the web interface displays a warning for you to do so:
+
+![](/ee/dtr/images/backup-warning.png)
 
 ### Back up image content