Using the data storage type defined on this page for raster images, read an image from a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)

Task: Use write ppm file solution and grayscale image solution with this one in order to convert a color image to grayscale one.

#! /usr/bin/perl
 
use strict;
use Image::Imlib2;
 
my $img = Image::Imlib2->load("out0.ppm");
 
# let's do something with it now
$img->set_color(255, 255, 255, 255);
$img->draw_line(0,0, $img->width,$img->height);
$img->image_set_format("png");
$img->save("out1.png");
 
exit 0;