[Plugin: Comment Control] used it to turn of comments on medial library

Used it to turn off comments on medial library. Thanks!! The spam is gone!

Force attachments to always inherit their comment status from their parent post.
(so if comments are closed on a post, then comments will also be closed on its attachments)

I have not tried it on regular post and pages.

http://wordpress.org/extend/plugins/comment-control/