Frequently Asked Questions

What's the difference between the Free and Pro versions?

In the free version, this “smart” replacement functionality is only available for WordPress’s built-in featured image (aka thumbnail) fields — so when you delete a duplicate file that’s embedded or linked somewhere else, such as in the body of a post, it may be “broken” on your site.

The Pro version has been extended to also intelligently replace images in many other locations, including references in the post body, gallery shortcodes, and extra fields from WooCommerce, JetPack, and Yoast SEO. Using Pro makes it much less likely that a deleted duplicate will have a negative effect on your site!

The Pro version also includes dedicated support from the Cornershop team.

Will Media Deduper Pro work on my site?

There are two important questions to consider when determining whether Media Deduper Pro will work on your site.

1. Are images hosted locally?

About 99% of the time, the answer to this question is yes. But some plugins or custom setups allow you to add externally hosted images — images hosted by another website — to your WordPress media library. 

Media Deduper Pro is not compatible with such a setup.

The files in your WordPress media library must exist on the same server as WordPress’s PHP files for Media Deduper to be able to analyze them and find duplicates.

If you use a third-party CDN to serve images to your visitors, don’t worry; That’s still fine as long as the original images remain on your web server.

2. Is your WordPress site accessible to the public? More specifically, is the site accessible to itself?

For the Media Deduper Pro indexer to run properly, your site needs to be able to establish an HTTP connection to itself, which is sometimes referred to as a “loopback” connection.

Plugins or hosting setups that require visitors to enter a password or accept/have a cookie in order to access your site may prevent Media Deduper Pro from analyzing and indexing your attachments.

For example, if your site is protected by HTTP basic authentication using an .htpasswd file, the MDD indexer will not be able to run without a bit of custom code (which we can provide).

Some “maintenance mode” plugins have also been known to interfere with the indexing process.

Still have questions about whether Media Deduper Pro will work for you? 
Please contact us.

How do you identify duplicate files?

Media Deduper scans each media library file and creates a unique code or “hash” based on the contents of the file itself. This means it finds duplicates based on the actual data in the file, not on the filename or any other associated information. It’s the only way to be sure!

Please note that the image data must be identical, not just similar.

For instance, Media Deduper will NOT consider two images to be duplicates if their brightness, resolution, or format (e.g. JPEG or PNG) differ, even if they are copies of the same original image.

How long does it take to build an index of my media library files?

When the plugin is first installed, it can take some time to completely scan existing media files to build the Media Deduper index, especially if you have many years’ worth of files in your library or many very large files (such as videos). This is because each distinct file receives its own index key.

Will this work to replace images in plugins?

Media Deduper Pro will intelligently replace images used in the stock WordPress “gallery” shortcode as well as in fields created by WooCommerce, JetPack, and Yoast SEO.

More plugin integrations are planned, but if you have any favorites that you’d like to make sure we’re working on, please let us know!

If you plan to use the feature to remove existing duplicates, then we would strongly recommend you purchase the Pro version, so you don’t end up with broken images on your site.

Will this delete unused image sizes?

Media Deduper only deletes unused media library files, and it does not delete unused image file sizes that are automatically created by WordPress.

Will Media Deduper Pro replace images stored in custom fields (a.k.a. post meta)?

Yes, but you’ll need to write some code of your own code to tell Media Deduper Pro which custom fields to look in and how images are stored there. 

Depending on your implementation, a custom field might reference an image by its post ID, or by its URL, or a field might contain image tags or shortcodes. 

Check out our documentation for the mdd_get_reference_fields filter to learn how to tell Media Deduper Pro which fields it should pay attention to and what type of data it should expect to find there.

Can Media Deduper Pro find duplicate images in custom post types?

By default, Media Deduper Pro will replace any images in any post type that was registered with the “public” parameter set to TRUE (see

If you have non-“public” post types that also might contain images that should be replaced, you’ll need to explicitly tell Media Deduper Pro about them. Check out our documentation to learn more about the mdd_get_reference_post_types filter and instructions.

What plugins do not work with Media Deduper Pro?

We are constantly updating Media Deduper Pro to be compatible with the most popular plugins on WordPress.  Currently, Media Deduper Pro is incompatible with:

Easy Fancybox
NextGEN Gallery
Page Builder by Site Origin
Responsive Lightbox
SiteOrigin Widgets Bundle
WP Retina 2x

This is not an exhaustive list of plugins that are not currently compatible with Media Deduper Pro. If you have a specific plugin that you have a question about, please contact us.

Is there a change log?

For a complete changelog for Media Deduper Pro, check out the version history page!

What if the plugin is not working for me?

If the plugin does not work on your site, please contact to request a refund.  Please note we can only honor refunds up to 30 days from purchase.

Cornershop can also provide customized support on your website at our standard maintenance rate of $200/hour.

Please note: As with any plugin that can perform destructive operations on your database and/or files, using Media Deduper can result in permanent data loss if you’re not careful. Back up your data before you use Media Deduper! Please!

Use this plugin at your own risk. The plugin developers are not responsible for any lost data or site issues as a result of using this plugin.