<?php
// Create a 100*30 image
$im = imagecreate(400, 300);

// White background and blue text
$bg = imagecolorallocate($im, 255, 255, 255);
$textcolor = imagecolorallocate($im, 0, 0, 255);

$w = filter_input(INPUT_GET, 'w', FILTER_SANITIZE_NUMBER_INT);

// Write the string at the top left
imagestring($im, 5, 0, 0, 'Hello ' . json_encode($w), $textcolor);

// Output the image
header('Content-type: image/png');

imagepng($im);
imagedestroy($im);