gdLib oddity

I'm building a site that generates images from what will be a database query. I've built this to create the relevant images

<?
// header
Header("Content-Type: image/gif");

// select image to build onto
switch ($baseimg){

case today:

  $im = ImageCreateFromGIF('/home/httpd/vhtdocs/iain/gdtest/todayball.gif');

		break;

case todaybonusball:

  $im = ImageCreateFromGIF('/home/httpd/vhtdocs/iain/gdtest/todaybonusball.gif');

		break;

case odd:

  $im = ImageCreateFromGIF('/home/httpd/vhtdocs/iain/gdtest/oddball.gif');

		break;

case oddbonusball:

  $im = ImageCreateFromGIF('/home/httpd/vhtdocs/iain/gdtest/oddbonusball.gif');

		break;

case even:

  $im = ImageCreateFromGIF('/home/httpd/vhtdocs/iain/gdtest/evenball.gif');

		break;

case evenbonusball:

  $im = ImageCreateFromGIF('/home/httpd/vhtdocs/iain/gdtest/evenbonusball.gif');

		break;

}

//create the text image
$text = imagecreate(40, 40);

// allocate colors
$white = imagecolorallocate($text, 250,250,250);
$black = imagecolorallocate($text, 0,0,0);

//create image to hold text
imagettftext ($text, 16, 0, 8, 28, $black, '/home/httpd/vhtdocs/iain/gdtest/arial.ttf', $draw);

//make transparent the background
$white = imagecolortransparent($text,$white);

imagecopy($im, $text, 0,0,0,0, 40,40);

imagedestroy ($text);
// output to browser

imagegif($im);

imagedestroy($im);
?>

Its called from a combination of these scripts at the moment.

<?php

function imgCreate($draw_array, $baseimg)

{
$bonusBall = array_pop($draw_array);

// loop for each item in array

foreach($draw_array as $draw){

echo "<img src=\"gdtest02.php?baseimg=".$baseimg."&draw=$draw\" border=0> ";

}

echo "<img src=\"gdtest02.php?baseimg=".$baseimg."bonusball&draw=$bonusBall\" border=0> ";

}

$todays_nums = Array();

$todays_nums[0] = "42";

$todays_nums[1] = "05";

$todays_nums[2] = "09";

$todays_nums[3] = "14";

$todays_nums[4] = "48";

$todays_nums[5] = "36";

$todays_nums[6] = "47";

$baseimg = today;

imgCreate($todays_nums, $baseimg);

But there is a real oddity in what is produced which I can only explain by directing you here

I can't figure out why it would be doing this at all. Why does it work for one but none of the rest?

It's for a piece called the Lottery Predictions if you're interested.

Cheers to anyone that can help.