By default, WordPress will create a page for each of the attachments you have in your media library (images, videos, pdf’s, etc.). With Memberium, you can easily disable those attachment pages by using “Disable Attachment Pages” option.
In order to disable attachment pages for media files, you’ll need to navigate to Memberium => Settings => Security tab and in there you would set “Disable Attachment Pages” option to YES.

In case you are are not familiar with attachments in WordPress, here’s more about that:
The term attachment is used for files uploaded to WordPress from post edit screen. When a file is uploaded using the Add Media button from post edit screen, that file automatically becomes an attachment of that particular post. Files uploaded directly to the Media Library are not particularly attached to a post or page. An attachment can be any file that can be uploaded using the media upload. (Read more)