Image in description deleted still accessible

Hello dear forum,

Someone updload a picture with sensible data into the description of a merge request.
He removes the picture but after some test, I discover that the picture url is still accessible if you are login.
Can someone help me to:
1- know policy for deleted documents from Gitlab? I try to find in the doc but nothing relevant
2- is there a possibility to easyly access all files or cleaning non-used documents?

Thank you very much for any help