Articles on: FAQs

Why FlyingCDN doesn't always deliver images in WebP

FlyingCDN may choose not to convert images to WebP for various reasons, often related to optimization efficiency, image characteristics, or technical limitations.

The Cf-Polished response header provides insights into the image processing and optimization attempts by FlyingCDN.

input_too_large: The input image exceeds the recommended size or complexity, requiring a reduction in resolution. It's suggested to use images smaller than 1,000 pixels and under 10 MB in PNG or JPEG format.
not_compressed: The image was already optimized to its fullest at the source, and therefore no additional compression was deemed necessary by the system.
webp_bigger: An attempt was made to convert the image to the WebP format, but it was found that the original JPEG or PNG version was already optimized efficiently at the source, or it was produced with a low-quality setting making the WebP conversion redundant.
cannot_optimize: The system encountered issues with the image, such as corruption or incompleteness, possibly due to problems at the origin server. It's advised to upload a fresh, intact version of the image.
format_not_supported: The image is in a format that is not supported (e.g., BMP, TIFF) or there's additional optimization software at the origin server that conflicts with the system's optimization process. Converting the image to a supported web format like PNG or JPEG and disabling any conflicting optimization software at the server may resolve this.
vary_header_present: The origin server is sending a Vary header with values other than 'accept-encoding', which could interfere with the system's functionality. To ensure compatibility, particularly for WebP support, it's recommended to disable WebP conversion at the server side and make sure that 'accept-encoding' is the sole value in the Vary header.

Updated on: 22/03/2024

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