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Troubleshooting Media Library and Image Display Issues After Using Smush

29 threads Sep 16, 2025 Plugin → Smush image optimization – optimize images | compress & lazy load images | convert webp & avif | image cdn

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Many WordPress users rely on the 'Smush Image Optimization – Optimize Images | Compress & Lazy Load Images | Convert WebP & AVIF | Image CDN' plugin to handle their image optimization. However, a common theme in community support forums involves images not displaying correctly in the Media Library or on the front end after using the plugin. This guide will walk you through the most frequent causes and their solutions, based on community-reported issues.

Common Symptoms

Users often report one or more of the following problems after installing or updating Smush:

  • Blank or missing image previews in the WordPress Media Library (both list and grid view).
  • Images not displaying in page builders, sliders (like Slider Revolution or NextGen Gallery), or custom post types.
  • JavaScript errors (e.g., "TypeError: Cannot read property 'strings' of undefined") in the browser console when trying to edit images.
  • Featured images being replaced by other gallery images on shop pages.
  • General critical errors or 500 internal server errors on pages related to media.

Why This Happens

These issues are rarely caused by the original image files being deleted. The 'Smush Image Optimization – Optimize Images | Compress & Lazy Load Images | Convert WebP & AVIF | Image CDN' plugin does not delete or rename original files. Instead, problems typically arise from:

  1. Thumbnail Generation: The optimization process can sometimes interfere with WordPress's ability to properly generate or display the various thumbnail sizes for an image.
  2. Lazy Load Conflicts: The Lazy Load feature, which delays loading images until they are in the viewport, can conflict with other plugins (especially sliders and galleries) that have their own loading methods.
  3. Plugin or Theme Conflicts: Incompatibilities with other active plugins, particularly those that also handle images (e.g., CDNs, other optimizers, Amazon S3 offload) or specific themes, can cause unexpected behavior.
  4. Caching: Sometimes, old cached versions of pages or media library data need to be cleared to reflect the optimized images.

How to Troubleshoot and Fix These Issues

1. Restore or Regenerate Thumbnails

If images are missing from the Media Library but are still on the server, the first step is to address the thumbnails.

  • Use Smush's Built-in Tool: Navigate to Smush -> Tools -> Restore Thumbnails. This will attempt to revert all thumbnails to their original, unoptimized state.
  • Regenerate Thumbnails: If the restore tool doesn't work, use a dedicated plugin like "Regenerate Thumbnails." After installing and activating it, go to Tools -> Regenerate Thumbnails and run the process. This will recreate all image sizes according to your theme's specifications.

2. Configure Lazy Loading Exclusions

Lazy Load is a common culprit for images not appearing in sliders, galleries, or custom post types.

  • Go to Smush -> Lazy Load.
  • In the Exclusions section, you can exclude specific pages or add specific image classes or file types (e.g., .png) from lazy loading. If a particular plugin's images are broken, try excluding the page where it appears or consult the plugin's documentation for the correct CSS class to exclude.
  • As a test, you can temporarily disable Lazy Load entirely to see if it resolves the issue.

3. Perform a Conflict Test

To rule out conflicts with other plugins or your theme, follow these steps:

  1. Deactivate all your plugins except Smush.
  2. Switch to a default WordPress theme like Twenty Twenty-One.
  3. Check if the problem persists. If it doesn't, reactivate your plugins one by one, checking each time to identify the conflicting software. Once identified, you can look for a more specific solution or exclusion for that plugin.

4. Clear All Caches

After making changes, clear all relevant caches:

  • Your WordPress caching plugin (if you use one).
  • Your browser cache.
  • Any server-side or CDN caches.

5. Check for JavaScript Errors

If you are comfortable with browser developer tools, check the console for errors when the problem occurs.

  • Right-click on the page and select "Inspect," then go to the "Console" tab.
  • Any red error messages here can provide crucial clues. Searching for these error messages online often leads to community solutions.

When to Seek Further Help

If none of the above steps resolve your issue, the problem might be more specific. When seeking help in community forums, be prepared to provide:

  • The exact error messages from your browser console or WordPress debug log.
  • A list of all active plugins and your theme name.
  • The URL of the page where the problem is visible.

Remember, the 'Smush Image Optimization – Optimize Images | Compress & Lazy Load Images | Convert WebP & AVIF | Image CDN' team frequently releases updates to address known conflicts. Ensuring your plugin is up to date is always a good first step before troubleshooting.

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