renaming files

[BOS45430]

Ok i have created a picture upload script.  THe problem is...is want to the pics to be renamed then stored.  I dont want any pic to have to same filename as any other ones.  How can I do this?  I thought about using rand but then there is a small chance that it could actually rename a file to something that already has that file name.  What about that autoincrement thing in mySql?  would that work?  please give me an example of how to do this.  Thanks!

[The Little Guy]

I use something like this for multiple file uploads:

<?php
foreach ($_FILES["image"]["error"] as $key => $error) {
if ($error == UPLOAD_ERR_OK) {
$tmp_name = $_FILES["image"]["tmp_name"][$key];

# Create a new file name

$string = "abcdefghijklmnopqrstuvwxyz0123456789";
$str = '';
for($i=0;$i<45;$i++){
	$pos = rand(0,36);
	$str .= $string{$pos};
}
$ext = getExt($_FILES["image"]["name"][$key]);
        $name = time().$str.$ext;

# End new file name

if(mysqli_query($db,"INSERT INTO friends_images 
(
	`ownerID`,
	`addDate`,
	`fileName`
) VALUES (
	'{$_SESSION['id']}',
	'$date',
	'$name'
)")or die(mysqli_error($db))){
$fullDir = "../../images/users/full/";
move_uploaded_file($tmp_name, $fullDir.$name);
list($width) = getimagesize($fullDir.$name);
}
}
?>