Following Marc's report regarding a missing image on themes i investigated and found the offending image was an image galleries one but image galleries weren't enabled.
I assumed someone had migrated them to image galleries so enabled file_galleries_redirect_from_image_gallery but that didn't work (so presumably the migration command hadn't been run) so i reenabled feature_galleries for now.
So next time a sysadmin is on ssh in there we could try it please?