This plugin allows attaching, unattaching or reattaching media data to different posts.
File Gallery extends WordPress media (attachments) capabilities by adding a new gallery shortcode handler with templating support (and much more).
Unattach, Reattach new actions in Media Library Table list to manage attachments
This plugin will allow you to attach a single file to multiple posts, but will also will allow you to detach any file.
Allows detaching images and other media from posts, pages and other content types.
Allows attaching and detaching images and other media to/from posts, pages and other content types.
Allows to unattach and reattach images and other attachments from within the media library page.