The shape-image-thresholdCSS property defines the alpha channel threshold used to extract the shape using an image as the value for shape-outside. A value of 0.5 means that the shape will enclose all the pixels that are more than 50% opaque.
the unique non-ambiguous order defined by the formal grammar
/* <number> value */
/* Global values */
Sets the threshold used for extracting a shape from an image. The shape is defined by the pixels whose alpha value is greater than the threshold. A threshold value outside the range 0.0 (fully transparent) to 1.0 (fully opaque) will be clamped to this range.