Why Are My NextGEN Gallery Images Blurry or Pixelated? Troubleshooting Guide

If you've noticed your NextGEN Gallery images appearing blurry, pixelated, or of lower quality than your original uploads, you're not alone. This is a common issue reported by users, and it can be caused by several factors. This guide will walk you through the most common causes and their solutions.

Common Causes of Poor Image Quality

Based on community reports, the primary culprits for blurry or pixelated images in NextGEN Gallery often relate to image processing, display settings, or conflicts with other software.

1. The Imagick PHP Library Conflict

A frequent cause of severe pixelation or corrupted, grey-barred thumbnails is a conflict with the Imagick PHP library on your server. The 'Photo Gallery, Sliders, Proofing and Themes – NextGEN Gallery' team has acknowledged this can be an issue.

Solution: You can disable NextGEN's use of the Imagick library to force it to use an alternative image processing engine (GD Library).

1. Access your website's files via FTP or your hosting provider's file manager.
2. Locate the wp-config.php file in the root directory of your WordPress installation.
3. Open the file for editing and add the following line of code above the line that says /* That's all, stop editing! Happy publishing. */:

   define('NGG_DISABLE_IMAGICK', true);

4. Save the file and upload it back to your server if necessary.
5. Finally, you must regenerate your thumbnails. Go to Gallery > Manage Galleries, edit the specific gallery, and use the "Create new thumbnails" option.

2. Incorrect Thumbnail Sizing and CSS Conflicts

Sometimes, blurriness is not a quality issue but a display issue. If your theme or another plugin forces thumbnails to be stretched or scaled by the browser, they will appear soft or blurry.

Solution: Investigate and fix CSS conflicts.

• Check the thumbnail dimensions you've set in your gallery display settings (NextGEN Gallery > Other Options > Image Options).
• Use your browser's inspect tool (right-click on a blurry image and select "Inspect") to see what CSS rules are being applied to the image. If the img element is being forced to a different size than its source file, you have a CSS conflict.
• A common fix is to add a custom CSS rule to override the problematic styling. Go to Appearance > Customize > Additional CSS and add code similar to this, adjusting the selector as needed:

  .ngg-widget img {
      width: auto !important;
  }

3. Color Profile and Pre-Upload Preparation

Differences in color and brightness between your original image and the gallery version can often be traced back to color profiles.

Solution: Before uploading, ensure your images are exported for the web using the sRGB color profile, which is the standard for web images. Most image editing software like Adobe Photoshop or Lightroom have an "Export for Web" or "Save for Web" function that handles this.

4. Third-Party Service Conflicts (CDNs)

If you use a Content Delivery Network (CDN) or an image optimization service that serves your images from a different domain, it can sometimes interfere with NextGEN Gallery's image generation and delivery, leading to quality loss.

Solution: Temporarily disable the CDN or image optimization service to see if image quality improves. If it does, you will need to check the configuration settings of that service or consult its documentation for serving WordPress images correctly.

Summary and Checklist

1. Try Disabling Imagick: Add define('NGG_DISABLE_IMAGICK', true); to your wp-config.php file and regenerate thumbnails.
2. Check Thumbnail Dimensions: Ensure the dimensions set in NextGEN settings match how they are displayed.
3. Inspect for CSS Conflicts: Use your browser's developer tools to see if images are being resized by CSS.
4. Export Images Correctly: Use the sRGB color profile when preparing images for the web.
5. Isolate Conflicts: Temporarily disable CDNs or other optimization plugins to test for conflicts.

Following these steps should resolve the majority of image quality issues encountered with the NextGEN Gallery plugin.