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Understanding and Troubleshooting LiteSpeed Cache Image Optimization Issues

20 threads Sep 16, 2025 Plugin → Litespeed cache

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LiteSpeed Cache is a powerful plugin for WordPress that offers a suite of performance enhancements, including its robust Image Optimization feature. However, users often encounter confusion and unexpected behavior when using this tool. This guide will explain common problems, why they happen, and provide practical solutions based on community experiences.

Common Image Optimization Issues and Their Causes

Many issues stem from misunderstandings about how the optimization process works. The plugin does not create new image sizes; it scans the database for existing images registered by WordPress (via functions like get_intermediate_image_sizes()) and optimizes them. Problems can arise from conflicts with other plugins, server settings, or the way the optimization data is managed.

Frequently Asked Questions and Solutions

1. Why are optimized images not displaying (e.g., still showing JPG)?

This is a frequent issue, often related to conflicts with other plugins.

  • Check for Plugin Conflicts: A common culprit is an offloading plugin like WP Offload Media. As seen in the sample threads, a primary troubleshooting step is to temporarily disable such plugins, clear all caches, and check if the optimized WebP/AVIF images then display correctly.
  • Verify Settings: Ensure the Image WebP Replacement option is turned on within the LiteSpeed Cache settings. Double-check that all images have been successfully pulled from the QUIC.cloud server and are present on your server.

2. How do I safely remove optimization files and start over?

Users wanting a "clean slate" often find that the "Destroy All Optimization Data" button does not remove all physical files.

  • Manual Cleanup Required: The "Destroy All Optimization Data" and "Remove All Original Image Backups" functions primarily clear the plugin's database tables (like wp_litespeed_img_optm). They may not delete all physical .webp and .bk.jpg files from your /uploads/ directory. For a completely fresh start, a manual deletion of these file types via FTP or your hosting file manager is often necessary.
  • Warning: Deleting .bk.jpg files means you lose your original, unoptimized images. You will not be able to re-optimize from the originals if you do this.

3. Can I optimize images in batches or exclude certain images?

Yes, the plugin offers flexibility.

  • Batch Optimization: You can optimize images in small batches. There is no requirement to process an entire library at once, which can help avoid timeouts on servers with limited resources.
  • Excluding Images: To prevent specific images from being optimized, you can manually restore them after optimization is complete. This involves:
    1. Using FTP/file manager to navigate to the image.
    2. Deleting the optimized file (e.g., image.jpg.webp) and the main optimized file (e.g., image.jpg).
    3. Renaming the backup file (image.bk.jpg) to the original name (image.jpg).
  • Excluding External Images: To stop the plugin from attempting to optimize external images (like YouTube thumbnails), which causes errors, you can add the following filter to your theme's functions.php file: 
    add_filter('litespeed_media_ignore_remote_missing_sizes', '__return_true');

4. Does it optimize all images on my site?

No. The LiteSpeed Cache image optimization feature works only on images that have been uploaded through the WordPress Media Library. Images placed in other directories via themes or other plugins (e.g., bb_medias/) will not be processed.

Key Takeaways

  • Backups are Crucial: Always back up your site before performing major operations like destroying optimization data or manually deleting files.
  • Plugin Conflicts are Common: If images aren't behaving as expected, systematically disable other plugins to identify conflicts.
  • Manual Intervention is Sometimes Needed: The plugin's reset buttons may not provide a full server-level clean slate, so be prepared to use FTP for complete file removal.

By understanding these common pitfalls and solutions, you can more effectively manage the LiteSpeed Cache Image Optimization feature and keep your site running smoothly.

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