I'm trying to increase load speed of the site so need to delete any unused media items.

However I have images that display as attached in the library although they are not. So bulk delete of unattached items is no use. Is there a way of finding or sorting definitively which images are actually on a current post or page, which are not, and then delete as needed?

Also there seems to be no way to view the title of an image from the site itself inside the editor - I can edit it and see the alt tags but not the actual title - this would be useful as a last way of seeing which images I have that are actually in use, regardless of misleading "unattached" or "attached" tags in the media library. 

Thanks!

Adam