set terminal png transparent crop enhanced

set output "psf.png"
set view map

unset surface
set style data pm3d
set style function pm3d
set ticslevel 0

set size square

set xrange [ 0 : 31 ] noreverse nowriteback 
set yrange [ 0 : 31 ] reverse nowriteback
set zrange [ 0 : 1 ] noreverse nowriteback

set pm3d implicit at b
set palette rgbformulae 30, 31, 32

splot "psf.img" matrix