captha.php

<?
header('Content-Type: image/jpeg');
$im = imagecreatetruecolor(175, 60);
imagefill($im, 0, 0, imagecolorallocate($im, 240, 240, 240));
for($i=0; $i<5; $i++)imagettftext($im, 16, 0, 10+30*$i, 40, imagecolorallocate($im, 100, 100, 100), 'arial.ttf', rand(0, 9));
imagepng($im);
imagedestroy($im);

//imagecreatetruecolor(width, height)
//imagefill(image, x, y, color);
//imagettftext(image, size, rotation, x, y, color, fontPath, char);
//imagecolorallocate(image, r, g, b)
//imagepng(image);
//imagedestroy(image);