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The auto parameter allows you to apply automatic conversions to your images. The following options are available:

  1. optimize
  2. format


When auto=optimize is set, Peakhour applies best-effort techniques to reduce the size of your image while maintaining a reasonable level of quality. The default quality setting is q=75. Additionally, the auto=format option is respected, so images will be served in the WebP format for browsers that support it.


With auto=format set, Peakhour will convert your images to a more optimal format for the web. Using browser signals and image analysis, the API will serve WebP images to browsers that support it, PNG images for those with transparency, and JPEG images for photographs in PNG format.