Stack Exchange doesn't allow users to delete answers that have been accepted by the question asker (a.k.a. original poster/OP). This is because - in the normal case - this is usually a bad thing to do. If the OP thinks the answer is useful to them, chances are it will be useful to other people, so it shouldn't be deleted.
There are sometimes exceptions to ...
With the Moderator Dashboard design changes, rolled out in 2019, you can expand the flagged post and see any images or YouTube videos linked in-line.
I posted an answer to the Formatting Sandbox, and flagged it myself to get you some screenshots. Here's the flag modal, not expanded:
Expanding the flag results in the following view:
I can ...