GD help

[Renlok]

Im trying (and failing) to make a pet recolouring script for a game.

 

<?php
//coords
$base_x = array(100);
$base_y = array(100);
$eyes_x = array(43, 20);
$eyes_y = array(83, 81);
$detail_x = array(20,24,28,39,34,39,48,44,57,56,95,91,98);
$detail_y = array(70,60,67,64,58,51,47,41,41,32,125,141,163);
//testing page
header ("Content-type: image/png");

$dogoverlay = imagecreatefrompng("images/misk-junk/dog-over.png");
$dogbase = imagecreatefrompng("images/misk-junk/dog-base.png");
$dogeyes = imagecreatefrompng("images/misk-junk/dog-eyes.png");
$dogdetails = imagecreatefrompng("images/misk-junk/dog-detail.png");
//get random colours to test with
$newcolour1 = imagecolorallocate($dogbase, 56, 160, 156);
$newcolour2 = imagecolorallocate($dogeyes, 253, 175, 4);
$newcolour3 = imagecolorallocate($dogeyes, 50, 207, 70);
$border = imagecolorallocate($dogbase, 10, 10, 10);
//recolour base
imagefilltoborder($dogbase, $base_x[0], $base_y[0], $border, $newcolour1);
//recolour eyes
for($i = 0; $i<count($eyes_x); $i++){
imagefilltoborder($dogeyes, $eyes_x[$i], $eyes_y[$i], $border, $newcolour2);
}
//recolour details
for($i = 0; $i<count($detail_x); $i++){
imagefilltoborder($dogeyes, $detail_x[$i], $detail_y[$i], $border, $newcolour3);
}

imagecopymerge($dogeyes,$dogbase,0,0,0,0,$width,$height,100);
imagecopymerge($dogdetails,$dogbase,0,0,0,0,$width,$height,100);
imagecopymerge($dogoverlay,$dogbase,0,0,0,0,$width,$height,100);
imagepng($dogbase,NULL,100); 
//clean up the image
imagedestroy($dogbase); 
imagedestroy($dogoverlay); 
imagedestroy($dogeyes); 
imagedestroy($dogdetails); 
?>

 

the problems i have are

- none of the images actually load up correctly, they either have a black background when its sposed to be transparent or they have random blobs of black in random places for no reason. No idea why this happens.

- all that shows is a wash off teal but i think thats caused because of the problems above.

 

and im new at using GD so i tend to make loads of really stupid mistakes. Also thanks in advance for any help.