w = 143
h = 188
name$ = "Mona_Lisa.jpg"
graphsize w,h
imgload w/2, h/2, name$
fastgraphics

for x = 0 to w-1
   for y = 0 to h-1
      p = pixel(x,y)
      b = p % 256
      p = p \256
      g = p % 256
      p = p \ 256
      r = p % 256
      l = 0.2126*r + 0.7152*g + 0.0722*b
      color rgb(l,l,l)
      plot x,y
   next y
   refresh
next x

imgsave "Grey_"+name$,"jpg"