An imgproxy preset is a named set of processing options. Presets can be used in [URLs](generating_the_url.md#preset) to make shorter and more human-readable.
Processing options should be defined in the same way they are defined in [URLs](generating_the_url.md#processing-options). For example, here's a preset named `awesome` that sets the resizing type to `fill` and the resulting format to `jpg`:
A preset named `default` will be applied to each image. This is useful when you want your default processing options to be different from the default imgproxy options.
Setting `IMGPROXY_ONLY_PRESETS` to `true` switches imgproxy into "presets-only mode". In this mode, imgproxy accepts a presets list as processing options just like you'd specify them for the `preset` option: