Update image uploaded script

Okay... lets see..

I have this image hosting script, I've been working on (with help from google, heh)

But there's a few things nagging me.

1) It can not upload .gif images?
2) The thumbnail looks ugly, can I add antialiasing? (antialiasing is the process where the pixels mix when resizing producing smooth lines i.e looks pretty)
3) (This one is not a mandatory request, but would be cool if someone knew how) Add on the generated thumbnails a small "bar" in the buttom (Like 15px heigh)saying: "Click to see full size" or something like that..
3)Do you have any other suggestions idea's to change some details to make this code better?
Also changing the script so it uses less resources but does the same wouldn't hurt either, heh

Here's the code:

<?php
if(isset($_POST['send']))
{
if($_POST['send'] == "ok") {
//tilladte filtyper. Tilføj fx. "image/gif"
$allowedTypes = array("image/jpeg", "image/pjpeg", "image/jpg", "image/gif");
$maxFileSize = 10240000; //tilladt max-størrelse i bytes
$max_width = 1024000; //Ja, tilladte max. højde
$max_height = 768000; //Tilladte max. bredde
//*nix-path til originalfilens endelige placering
$path = $_SERVER['DOCUMENT_ROOT'] . "/";
IF($_FILES['img']['size']> 0)
{
//Er fil-typen blandt tilladte?
IF (in_array($_FILES['img']['type'],$allowedTypes))
{
//Er fil-størrelsen under max. tilladte?
IF ($_FILES['img']['size'] <= $maxFileSize)
{
//Find billedets størrelse
$size = getimagesize($_FILES['img']['tmp_name']);
//Filen er ikke for bred
if($size[0] < $max_width)
{
//Filen er ikke for høj
if($size[1] < $max_height)
{
//Læseligt tidsstempel - tilføjes senere filnavn og giver derved et unikt filnavn
$tid = date("His_dmy", time());
//Udregn skaleringsforholdet på thumb, her skal 100 rettes til den ønskede bredde
$new_w = 125;
$division = $size[0] / 100;
$new_h = $size[1] / $division;
//Lav et nyt billede så vi kan komme igang
$dst_img=ImageCreateTrueColor($new_w,$new_h);
$src_img=ImageCreateFromJpeg($_FILES['img']['tmp_name']);
//Smid noget indhold i, og resize
ImageCopyResized($dst_img,$src_img,0,0,0,0,$new_w,$new_h,ImageSX($src_img),ImageSY($src_img));
//*nix-path til thumbfilens endelige placering
$filename2 = "thumbs/" . $img=$tid.$_FILES['img']['name'];
//Udfør det hele
//echo "dst_img=".$dst_img." ";
//echo "filnavn2=".$filename2." ";
ImageJpeg($dst_img, $filename2);
//Flyt filen fra tmp til endelig placering
move_uploaded_file($_FILES['img']['tmp_name'], $path.$tid.$_FILES['img']['name']) or die("There has happend an mistake!");
echo "<center> Thumbnail Code: <input type='text' class='textfield' onClick='highlight(this);' style='width: 400px' size='70' value='['name']."] [MySite.com] ' /> 
Signature Code / Show Image: <input type='text' class='textfield' onClick='highlight(this);' style='width: 400px' size='70' value=' ' /> 
Direct Link To Image: <input type='text' class='textfield' onClick='highlight(this);' style='width: 400px' size='70' value='http://MySite.com/".$tid.$_FILES['img']['name']." ' /> (<a href='http://MySite.com/".$tid.$_FILES['img']['name']." '>check</a>) Preview:<a href='/".$tid.$_FILES['img']['name']."'><img border='0' src='".$filename2."'></a></center> ";
if(isset($_POST['tekst']))
{
echo $_POST['tekst'];
}
}
ELSE
{
//Fejlmedl. hvis fil over max. tilladt
$fejl = "Billede ikke sat ind: Filen er for høj!";
}
}
ELSE
{
//Fejlmedl. hvis fil over max. tilladt
$fejl = "Billede ikke sat ind: Filen er for bred!";
}
}
ELSE
{
//Fejlmedl. hvis fil over max. tilladt
$fejl = "The file is too big!";
}
}
ELSE
{
//Fejlmedl. hvis fil-format ikke tilladt
$fejl = "Wrong File! We only allow: .jpg .gif and .png!";
}
}
}
}
if(isset($fejl))
{echo $fejl;
}
?>