<?php
declare(strict_types=1);

$image = imagecreatetruecolor(8, 6);
$gray = imagecolorallocate($image, 100, 100, 100);
imagefill($image, 0, 0, $gray);
imagegammacorrect($image, 1.0, 1.0);
$pixel = imagecolorsforindex($image, imagecolorat($image, 0, 0));
echo $pixel["red"], ",", $pixel["green"], ",", $pixel["blue"], "\n";
