Performance Foundry Support Hub

Troubleshooting Thumbor Images

Normally, Thumbor works without a hitch, but there are some cases where it can be a problem:

Images won't appear in some browsers

Thumbor will intelligently serve the best image format to different browsers. In practise, this normally means serving standard jpegs to some browsers and webP files to others. However, if you hard-link to the webP version of the image, this will always load... and that means it won't load in browsers that don't support it. 

To fix, look in your post or setting, and replace any references to .webp with the original file ending (.jpg, .jpeg, .png, or other). Thumbor will still automatically load webP where it can.

If you have a lot of references to webP, ask our support to replace these for you.

Images in the media library are blank

On rare occasions, Thumbor will not be correctly set up to allow the image size in your media library: please contact support to have it reconfigured.

A report tells me that large images are being loaded, or resized in the browser

One cool thing about Thumbor is that it will automatically create new images in the size that's requested by your code. So if we're seeing issues with images being too large, it means your code is likely requesting very large images.

WordPress natively uses scrsets to offer browsers different image sizes for different screens. These are controlled in the Settings > Media option of WordPress. You can also add additional, custom scrset sizes in the Images tab of Foundry Anvil. (Don't add too many, or your code will become very bloated.)

If you still can't get a good result, contact support. It could be that something, somewhere is using non-standard code to output images, and it needs customisation. 

Images look fuzzy on some screens

This is the same issue as above, but in reverse: the image is too small. You can add some new custom srcsets or contact support to help out.

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