Graphics Php

First code, the one that generates the code and checks it. Save as "numverify.php".
---
#################
# numverify.php #
#################
if (!$num_ent)
{
$nums = array("5","6","7","8","d","e","1","2","3","4","f","g","h","i","j","k","9","0","a","b","c","l","m","n","o","p","q","x","y","z","A","B","C","D","r","s","t","u","v","w","E","F","G","N","O","P","Q","R","S","H","I","J","K","L","M","T","W","X","Y","Z","U","V");
// Creates 10 random array access keys to nums.
$random_key = array_rand($nums, 10);
$random = "";
for ($i=0;$i<10;$i++)
{
// Uses random access keys to access 10 random elements in the array.
$random = $random . $nums[$random_key[$i]];
}
echo "";
echo "

Please type the code you see above. (CASE-SENSITIVE)


";
}
else
{
if ($num_ent == $random)
{
// Af they get it right ...
echo "Correct!";
}
else
{// And if they get it wrong ...
echo "Incorrect. Go back and refresh the page for a new code.";
}
}
?>
---
Second code, the one that generates image. Save as "pic.php".
---
###########
# pic.php #
###########
header("Content-type: image/png");
$im = @imagecreate(95, 18) or die("Cannot Initialize new GD image stream");
// 95,18 is the size of the image;
// height,width. Must be changed if
// font is changed.
$background_color = imagecolorallocate($im, 225, 225, 225); // background color R,G,B
$text_color = imagecolorallocate($im, 233, 14, 91); // text color R,G,B
imagestring($im, 5, 1, 0, $random, $text_color); // "5" is the font, can be changed
// 0-1, but the size changes to the
// dimensions must be changed. 1,0
// is the x,y location.
imagepng($im);
imagedestroy($im);
?>