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WP-SEO-Redirect-301 is a WordPress plugin that remembers your old urls and redirects users to the updated url, to prevent 404s when urls change
If you click on “SEO Redirect 301” menu link, you will see a list of old urls pointing to the new ones. Its here where you can delete ones you don’t want anymore.
Since version 1.9, you now get a sitemap that you can submit to google and bing. After installing the plugin, you can submit http://yoursite/301-sitemap.xml to google or bing.
Since version 1.8.0, you can now create custom urls in your admin post/page edit page. Login to your wordpress site, go to any post/page and scroll down. You should find a Meta Box called SEO Redirect 301s. If you submit a url here and then browse to this url, it will redirect you to the page/post your editing.
If you wish to manually submit a alias slug, make sure that you are using the Code Editor, not the Visual Editor. Edit the page or post, click on its 3 dots icon and click on Code Editor. Scroll down page until you see SEO Redirect 301s. Its here where you can manually enter in an alias slug.
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WP SEO Redirect 301

WP-SEO-Redirect-301 is a WordPress plugin that remembers your old urls and redirects users to the updated url, to prevent 404s when urls change

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.

WP SEO Redirect 301 vs Attachment Pages Redirect