Moderate comment on a picture

Comments in general do not feature an approval mechanism up until WoltLab Suite 3.0. However, WoltLab Suite 3.1 makes quite a lot of improvements in this direction: Comment Improvements and User Profile Cover Images

What do you mean with "moderation on comment"? If you refer to reporting existing comments, that is already possible using the exclamation mark icon when hovering over a comment:

If you refer to approving comments before they are published, that will be a new feature introduced with WoltLab Suite 3.1 (see Comment Improvements and User Profile Cover Images).

PS: Alexander Ebert was faster than me as I was taking my time to make the screenshot

That is the warning feature which is not available for comments at the moment. Feel free to create a suggestion to add that feature.