Watermark Y Position
mark-y
Defines the y-position of the watermark in relation to the top-most edge of the base image.
The value can be positive or negative, written either as a whole number of pixels or as a decimal fraction of the image (see below). If the value is negative, the image will be partially outside the base image boundary. The mark-y parameter will overwrite mark-align=top, mark-align=middle, mark-align=bottom, and mark-pad (in the vertical direction) if set. Use mark-y[N] to style a specific additional watermark layer — styles do not inherit across watermark 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.