I have used multiorphan to determine what media files are orphans. I try not to delete these files becuase they might actually be an image we need. So I make a manual list of the images and locations and then use Move tree for media to move the images into a new directory "unused_media_files" At one point I had over 900 files, since then after confirming things, I whittled it down considerably.
Multiorphan would benefit from allowing users to move an orphan image file to "unused_media_file" directory rather than "Delete" Who wants to figure out how to get the media back if it is needed?
The other tool I used was BatchEdit, which allows me to search on media files with {{opencpn:unused_media_file from certain namespaces to see if there are media links back to the unused_media_file directory so that I can identify what media should be moved back to a certain namespace and I make the move with MOVE treeview.
I also have to check between namespaces in our wiki to make sure that the images for a given namespace are all contained within that namespace, to make operations like siteeport and epub more efficient and work better. For example, our Basic_Manual and Advanced_Manual have to be made into packages so we should have all the image needed under each of those namespaces to begin the process of packaging for offline use.
We really need a plugin tool that will help use easily identify these wayward media files and move them to the right namespace.