Input samples must be in byte (unsigned char) format. Preprocess data
with sfbyte first, if they have float or other samples. Only first 2D
section (n1 x n2) is taken from input data, the rest is ignored.
Use sfwindow and/or sftransp to generate input in adequate order.
o1, o2, d1, and d2 are ignored; data are treated by GIMP as equally
Be advised, that a greyscale image file is created; not every
GIMP plugin is capable of working with greyscale input.