Product Personalizer uses Shopify’s CDN to save personalized images and Uploaded images by Customer.
Shopify recently introduced  .webp format (see the newsletter here )

Shopify automatically changes the filetypes to .webp

To save the images as the original file type do the following

  • Go to the Orders in the Shopify Dashboard
  • Click on an Order
  • Over the image right click > save link as…

This will save the image as the original file type and not .webp