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Transparent .pngs with colour type Palette cannot be converted #1864
Description
Bug Description
When uploading images, with the color type "Palette" or "PaletteAlpha", the plugin generates the full size-webp versions as an empty files (0 bytes). The resized versions are converted correctly. This results in images not being displayed to site visitors, as the .webp file is invalid.
Steps to Reproduce
Upload an image with the color type "Palette" or "PaletteAlpha" to the WordPress media library.
Navigate to the directory where the image is stored (e.g., /wp-content/uploads/2025/02/).
Observe that the corresponding .webp version of the image has a file size of 0 bytes.
As a result, the image is not displayed to site visitors.
Additional Notes
Converting the image to a different color type to sRGB before uploading resolves the issue for me.
Example
-rw-r--r-- 1 someuser someuser 858 2025-02-07 08:18 image-name-150x150.webp
-rw-r--r-- 1 someuser someuser 25160 2025-02-07 08:18 image-name-1536x864.webp
-rw-r--r-- 1 someuser someuser 2052 2025-02-07 08:18 image-name-300x169.webp
-rw-r--r-- 1 someuser someuser 9086 2025-02-07 08:18 image-name-768x432.webp
-rw-r--r-- 1 someuser someuser 33812 2025-02-07 08:18 image-name.png
-rw-r--r-- 1 someuser someuser 0 2025-02-07 08:18 image-name-png.webp
Activity
swissspidy commentedon Feb 11, 2025
Could you please share details about your PHP and GD/ImageMagick versions? That will help others trying to reproduce this.
swissspidy commentedon Feb 11, 2025
Actually, looks like a possible duplicate of #1561
benniledl commentedon Feb 11, 2025
PHP Version 8.2.27
GD Version | bundled (2.1.0 compatible)
Imagick 3.7.0
Neither GD or Imagick work
adamsilverstein commentedon Jul 19, 2025
@benniledl - can you check if the patch in #2024 fixes your issue?
westonruter commentedon Aug 15, 2025
@benniledl I prepared a ZIP build of the plugin you can use to install via WP Admin > Plugins > Add Plugins > Upload Plugin.