What are you trying to do?
You cannot delete a media object when it is linked to a family tree. You have to delete the link first.
If you don’t know where the link is, or think you have already removed the link, then you can search for it in your database. Search the xx_media table. Look for “A6092-1.png” in the m_filename column. Then the m_gedcom column will show you the GEDCOM link.