gan ane lg belajar upload image pke php coding nya kira2 begini

uploadform.php

<form name="form" method="post" enctype="multipart/form-data" action="uploadstatus.php">

Image : <input name="gmbr" type="file" />

<input type="submit" name="upload" value="Upload" />

</form>

dan
uploadstatus.php

<?php

require("conn.php");



$fileName = $_FILES['gmbr']['name'];

$fileSize = $_FILES['gmbr']['size'];

$fileError = $_FILES['gmbr']['error'];

if($fileSize > 0 || $fileError == 0){

$move = move_uploaded_file($_FILES['gmbr']['tmp_name'], 'img/'.$fileName);

if($move){

echo "<div align='center'><h1>upload Sukses<h1></div>";

$sql="insert into pic values('',$fileName'";

$result = mysql_query($sql);

} else{

echo "<div align='center'><h1>Upload Gagal<h1></div>";

}

} else {

echo "<div align='center'><h1>upload Gagal<h1><br>Failed to Upload : $fileError </div>";

}

?>

ane dah suskes, tp msih ada kendalanya yaitu saaat ane upload gmbr dengan nama yg sama maka gambar yg lama akan ilang ketimpa oleh gmbr yg baru..
misalnya :
ane uplod gmbr pe1 asd111.jpg => gmbr kucing
ane uplod gmbr ke2 asd121.jpg => gmbr tikus
ane uplod gmbr ke3 asd234.jpg => gmbr kambing
ane uplod gmbr ke4 asd121.jpg => gmbr kodok

ketika di show,, gmbr ke 2 dn ke yg 4 itu kluarnya gmbr kodok semua,, krna pada saat proses upload nama file mereka sama walaupun gmbr nya beda..
file asd121.jpg(gmbr tikus) hilang.. tertimpa(overwrite) oleh file asd121.jpg(gmbr kucing)..
nah itu gmn ya gan solusinya?? cara nambah kondisi jika ada file yg namanya sama lgsng otomatis namanya jd berubah misal jd
asd121.jpg
asd121(2).jpg
asd121(3).jpg
asd121(4).jpg
dst..

bantu ane gan..