imagegif()

hi,
have installed the gd lib. and i can use them
but i can't use imagegif() , here is the error
Fatal error: Call to undefined function: imagegif()
and here is the code
<?
$fn='index1.gif';
if(isset($fn)){
$ext = substr($fn, -3);

if($ext == 'jpg'){
$mime = "image/jpeg";
}
elseif($ext == 'gif'){
$mime = "image/gif";
}
elseif($ext == 'png'){
$mime = "image/png";
}
else{
exit("<b>Unkown format!</b><br/>\n");
}

function resize($fn, $mime, $vraz){
header("Content-Type: ".$mime."\n\n");

list($width, $height, $value, $params) = GetImageSize($fn);

$new_width = ceil($width/$vraz);
$new_height = ceil($height/$vraz);

$new_width2 = ceil($width/$vraz)."0";
$new_height2 = ceil($height/$vraz)."0";

if($mime == 'image/jpeg'){
$newImage = ImageCreate($new_width, $new_height);
$cpyImage = ImageCreateFromJPEG($fn);
ImageCopyResized($newImage, $cpyImage, 0, 0, 0, 0, $new_width, $new_height, $width, $height);

ImageJPEG($newImage);
}
elseif($mime == 'image/gif'){
$newImage = ImageCreate($new_width, $new_height);
$cpyImage = ImageCreateFromGIF($fn);
ImageCopyResized($newImage, $cpyImage, 0, 0, 0, 0, $new_width, $new_height, $width, $height);

ImageGIF($newImage);
}
elseif($mime == 'image/png'){
$newImage = ImageCreate($new_width, $new_height);
$cpyImage = ImageCreateFromPNG($fn);
ImageCopyResized($newImage, $cpyImage, 0, 0, 0, 0, $new_width, $new_height, $width, $height);

ImagePNG($newImage);
}
else{
exit("<b>Unkown format!</b><br/>\n");
}
}

resize($fn, $mime, 100);
}
else{
exit("<b>Please select file!</b><br/>\n");
}
?>


can u please help me ?!

 

how can i install the imagegif() function in to my gd lib. ?
i want to resize a picture with this code .
can you send me please some codes to resize an image without imagegif() function ?

 

the picture created by this code , has not a good quality. ( color is not real) can you please help me ?!?