The plugin lets you configure image optimization, CSS and JavaScript minification, CSS and JavaScript concatenation, exclusions, and background processing from your WordPress admin dashboard.

When to use this guide

This guide is useful when you want to:

  • Enable image optimization
  • Configure WebP or AVIF output
  • Enable CSS or JavaScript minification
  • Test concatenation safely
  • Add exclusions for files that should not be optimized
  • Check background optimization progress

Prerequisites

Before configuring the plugin, make sure you have:

Access the plugin settings

To open the plugin settings:

  1. Log in to your WordPress admin dashboard.
  2. Go to Performance from the left sidebar.
  3. Open the tab you want to configure.

Configure image optimization

Use Image Optimization to control how the plugin optimizes Media Library images.

Before enabling image optimization, decide:

  • Which image types you want to optimize
  • Whether to generate WebP or AVIF versions
  • Which quality level to use
  • Whether to optimize images automatically on upload
  • Whether to keep or delete original image files
  • Whether any images should be excluded

To configure image optimization:

  1. Go to Performance > Image Optimization.
  2. Review the available image format options.
  3. Select the image types you want to optimize.
  4. Choose the output format, such as WebP or AVIF.
  5. Set the image quality level.
  6. Choose whether to keep original image files.
  7. Add exclusions for images that should not be optimized.
  8. Save your changes.

For more detail on image formats, quality settings, automatic optimization, and exclusions, see Image optimization via the Performance Plugin.

Configure CSS and JavaScript minification

Use Minification to reduce the size of CSS and JavaScript files. Minification removes unnecessary characters such as whitespace, comments, and line breaks.

To configure minification:

  1. Go to Performance > Minification.
  2. Enable CSS minification if you want to optimize stylesheets.
  3. Enable JavaScript minification if you want to optimize scripts.
  4. Add exclusions for files that should not be minified.
  5. Save your changes.
  6. Test key pages on your site.

Test pages that include forms, checkout flows, sliders, popups, maps, menus, or custom scripts.

If a script or layout breaks, disable the related setting and add an exclusion for the affected file.

For more details on how minification works, see Optimize CSS and JavaScript with the Performance Plugin.

Configure CSS and JavaScript concatenation

Use Concatenation to combine multiple CSS or JavaScript files into fewer files.

Concatenation can reduce the number of browser requests needed to load a page, but it can also affect how assets load.

Important: Concatenation is a beta feature. Test it carefully before using it on a production site.

To configure concatenation:

  1. Go to Performance > Concatenation.
  2. Confirm that minification has already been tested.
  3. Enable CSS concatenation only if needed.
  4. Enable JavaScript concatenation only if needed.
  5. Add exclusions for files that should not be combined.
  6. Save your changes.
  7. Test important pages and interactive elements.

If you notice broken layout, missing styling, or JavaScript issues, disable concatenation and exclude the affected files before testing again.

For more detail on how concatenation works and when to use it, see Optimize CSS and JavaScript with the Performance Plugin.

Add exclusions

Use exclusions when a file, asset, or image should not be optimized.

Exclusions are useful for:

  • Theme scripts
  • Page builder assets
  • Form scripts
  • Slider scripts
  • Popup scripts
  • Map scripts
  • Checkout scripts
  • Tracking or third-party scripts
  • Images that must keep their original format or quality

Depending on the setting, you can exclude items using direct URLs or regular expressions.

To add an exclusion:

  1. Open the tab for the optimization type.
  2. Find the exclusion field.
  3. Add the file URL, image URL, or matching pattern.
  4. Save your changes.
  5. Test the affected page again.

Use the narrowest exclusion possible. Excluding one affected file is better than disabling an entire optimization feature.

For CSS and JavaScript exclusion guidance, see CSS and JavaScript optimization with the Pressidium Performance Plugin.

For image exclusions, see Automatic image optimization via the Performance Plugin.

Monitor background processes

Use Background Processes to check optimization work running behind the scenes.

The plugin uses background processing for image and asset optimization so heavy processing does not run directly during page load.

To monitor background processes:

  1. Go to Performance > Background Processes.
  2. Check whether tasks are queued, running, paused, or completed.
  3. Allow large optimization jobs to finish before making more changes.
  4. Review the affected pages after processing completes.

Large media libraries or sites with many assets may take longer to process.

Review logs

Use Logs when diagnosing plugin behavior.

Logs can help when:

  • A file is not being optimized
  • A background task appears delayed
  • An optimization setting does not behave as expected
  • You need more context before contacting Support
  • A developer needs to review plugin activity

To review logs:

  1. Go to Performance > Logs.
  2. Check for entries related to the affected optimization.
  3. Note any relevant messages before contacting Support.

For most sites, use this order:

  1. Configure image optimization.
  2. Test image output on key pages.
  3. Enable CSS minification.
  4. Test layout and styling.
  5. Enable JavaScript minification.
  6. Test forms, menus, checkout, and interactive elements.
  7. Review concatenation only if you need additional request reduction.
  8. Monitor background processes.
  9. Use logs if something does not behave as expected.

Common issues and solutions

Settings do not save

Check that your WordPress user has administrator permissions.

Then refresh the WordPress admin dashboard and try again. If the issue persists, check whether another plugin is interfering with the settings page.

Settings are saved but do not appear to take effect

Clear any active cache and test again.

If the setting depends on background processing, open Performance > Background Processes and check whether tasks are still queued or running.

A page breaks after enabling minification

Disable the related minification setting and test the page again.

If the page works again, add exclusions for the affected CSS or JavaScript files before re-enabling minification.

A page breaks after enabling concatenation

Disable concatenation and test the page again.

If the issue disappears, keep concatenation disabled or add exclusions for the affected files before testing again.

Images do not look correct after optimization

Review the image quality setting and check whether the original files are still available.

If needed, exclude the affected images or adjust the quality level before optimizing again.

Best practices

  • Start with the default settings.
  • Enable one feature at a time.
  • Test important pages after each change.
  • Use staging before production when possible.
  • Keep original images until you confirm the optimized output.
  • Treat concatenation as advanced and beta.
  • Use exclusions instead of disabling an entire feature when only one file causes an issue.
  • Check Background Processes after enabling image or asset optimization.
  • Review Logs before escalating a plugin issue.

Need help?

If an optimization causes an issue you cannot resolve, contact Support and include:

  • Site URL
  • WordPress version
  • Plugin version
  • Optimization setting that caused the issue
  • Affected page URL
  • Screenshot of the issue
  • Browser console errors, if available
  • Relevant log entries
  • Any files you already excluded

For plugin bugs or technical feedback, you can also use the official WordPress.org support forum or GitHub Issues.

Where to go next

After you configure the Pressidium Performance Plugin, review the related optimization guides or check for issues if the site does not behave as expected.