sizeN sizen

Normalized Size. Used to specify image sizes or rectangle sizes, normalized relative to the size of layer 0 or some other image.

nx , ny
nx , ny
normalized width and height relative to another image (real, real, greater than 0)

Both nx and ny must be greater than 0. 0,0 may indicate that a specific default size should be used. 1,1 specifies a size equal to the reference image.