import java.awt.image.*
b=list(project(range(255,0), byte))
invert_op = LookupOp(ByteLookupTable(0,[b,b,b]), null)

function invert(imagefile, dest){
  im = readImage(imagefile)
  im2 = makeImage(im.width, im.height, null, im.type)
  invert_op.filter(im, im2)
  writeImage(im2, dest)
}

invert("white-pants.jpg", "black-pants.jpg")