By default, it is not. But you can modify the Journal Template to display comments.
1. Open the Active Social Control Panel
2. Click on Journal
3. Click on the word Photos, in the list of Journal Types
4. Click the templates tab.
5. Click Summary
6. Paste this near the end of the line of html, right before the < /table > tag.
<tr><td></td><td>[AS:CONTROL:COMMENT]</td></tr>
7. Click save.
8. Exit and view the summary.
You will still have to make sure your comment permissions are configured correctly though.