Michael Thomas

404 errors are generally very ‘expensive’ on WP sites as they cause WP to run on every attempt, slowing 
down your site and causing additional load on your web hosting environment.
WP Speed 404 can either suppress or log and email any 404 errors affecting your site under wp-content, wp-admin and 
wp-includes (configurable).

WP Speed 404

WP Speed 404 can either suppress or log any 404 errors affecting your site under wp-content, wp-admin and wp-includes (configurable).

Brad Parbs

surfboards

Quickly output a 404 for static files that aren’t found, rather than loading the normal 404 page.
Any static files ( images, text, pdfs, etc ) that don’t exist will 404 as soon as possible, rather than loading the entire WordPress application.
<h3>Details</h3>
By default, the list of extensions to check are the results of <code>wp_get_ext_types</code>, but can be filtered with <code>static_404_extensions</code>.
The output is a static page with the text <code>404 Not Found</code>, this text can be edited by filtering <code>static_404_message</code>.
A 404 status code will be used, but can be filtered with <code>static_404_response_code</code>.
Passing true to <code>static_404_should_process_request</code> will short-circuit and skip processing the request. This filter gets passed the current request.

Static 404

A WordPress plugin to quickly send a 404 for missing static files.

WP Speed 404 vs Static 404