Errors encountered during Image Optimizer processing.

Fastly writes this header into responses. It is proprietary to Fastly.

This header is written by Fastly when a fatal error occurs in Image Optimizer. The following error scenarios will prevent the image from being processed:

  • Image exceeds maximum dimensions
  • Image could not be parsed
  • Not a supported image format
  • Unsupported Content-Encoding
  • Gzipped body exceeds maximum length
  • Gzipped body could not be decoded
  • Invalid status
  • Response is pass
  • Response is not cacheable