IA 4.0 doc

            An array of actions to perform.  Each action is
            either a string (i.e. { actions: [ 'solarize' ] })
            , or an object with a single property, where the
            property name is the action to perform, and the
            property value is the argument (i.e. { actions:
            [{rotate: 90}] }.  Supported actions include:
            contrast -- adjust the image's contrast, accepts
            an optional numeric argument between -10 and 10 |
            crop -- select a subset of an image, accepts an
            array of four floating point numbers: x1,y1,x2,y2
            which are between 0.0 and 1.0 and are relative
            coordinates to the upper left hand corner of the
            image | despeckle -- reduces the speckle noise in
            an image while perserving the edges of the
            original image, accepts no arguments | enhance --
            Applies a digital filter that improves the quality
            of a noisy image, accepts no arguments  |
            grayscale -- remove the color from an image,
            accepts no arguments | greyscale -- an alias for
            'grayscale' | negate -- negate the colors of the
            image, accepts no arguments | noop -- do nothing. 
            may be applied multiple times.  still does
            nothing. | oilpaint -- an effect that will make
            the image look like an oil painting, accepts no
            arguments | psychodelic -- trip out an image. 
            takes no arguments.  may be applied multiple
            times. | rotate -- rotate an image by some number
            of degrees, takes a single numeric argument |
            scale -- downscale an image preserving aspect
            ratio.  you may provide the integer arguments
            maxwidth and/or maxheight which limit the image in
            the specified direction.  units are pixels. |
            sepia -- sepia tone an image.  no arguments. |
            solarize -- solarize an image.  no arguments |
            swirl -- swirl an image.  optionally a numeric
            argument specifies the degrees to swirl, default
            is 90 degrees. |