Blend Y Position
blend-y
Positions the overlay layer vertically, measured from the top edge of the base image in pixels.
The default value is 0. Note: blend-y is not applicable to color overlays—they apply to the entire image. Use blend-y[N] to style a specific additional blend layer — styles do not inherit across blend layers.
This parameter accepts a relative length: a whole number is pixels, and a decimal between -1 and 1 is a fraction of the base image’s height.