Samuel Aguilera

There are three possible scenarios where this plugin does something. In all cases, the attachment page must exists, the plugin will not run for deleted attachments:
A) A visitor lands on an attachment page and the parent post is available (not in trash or deleted). A 301 redirect will be issued to redirect the visitor to the parent post.
B) A visitor lands on an attachment page and the parent post was already deleted from trash. A 302 redirect is issued to home page (this can be changed to 301 if you want, see FAQ for more details).
C) A visitor lands on an attachment page and the parent post is in trash, therefore not available for the visitor. It returns a 404 error code to prevent endless redirection loop in old WP releases and redirecting to trashed/not available posts.
There is no options page, simply activate it and will do the job.
If you’re happy with the plugin <a href="https://wordpress.org/support/plugin/attachment-pages-redirect/reviews/?filter=5" rel="ugc">please don’t forget to give it a good rating</a>, it will motivate me to keep sharing and improving this plugin (and others).
<h4>Requirements</h4>
<ul>
<li>WordPress 4.8 or higher.</li>
</ul>

Attachment Pages Redirect

Redirect attachment pages or return a 404 error for them based on the parent post status.

Attachment Pages Redirect vs 404 Solution