PHP如何更改/添加图像标题

我是php的新手，我已经下载了一个免费的图像库源代码。它有管理帐户，你可以在上面上传图像。现在，当我上传图像时，它生成随机图像标题，如数字'4849404'。我希望它为每个图像分配一个特定的标题。我该怎么做呢?如果我没记错的话，这里应该是图片标题的行:

$RandomNumber   = rand(0, 9999999999); // We need same random name for both files.
// some information about image we need later.
$ImageName      = strtolower($_FILES['ImageFile']['name']);
$ImageSize      = $_FILES['ImageFile']['size']; 
$TempSrc        = $_FILES['ImageFile']['tmp_name'];
$ImageType      = $_FILES['ImageFile']['type'];
$process        = true;

//Validate file + create image from uploaded file.
switch(strtolower($ImageType))
{
    case 'image/png':
        $CreatedImage = imagecreatefrompng($_FILES['ImageFile']['tmp_name']);
        break;      
    case 'image/gif':
        $CreatedImage = imagecreatefromgif($_FILES['ImageFile']['tmp_name']);
        break;
    case 'image/jpeg':
        $CreatedImage = imagecreatefromjpeg($_FILES['ImageFile']['tmp_name']);
        break;
    default:
        die('Unsupported File!'); //output error
}
//get Image Size
list($CurWidth,$CurHeight)=getimagesize($TempSrc);
//get file extension, this will be added after random name
$ImageExt = substr($ImageName, strrpos($ImageName, '.'));
$ImageExt = str_replace('.','',$ImageExt);
$BigImageMaxWidth       = $CurWidth;
$BigImageMaxHeight      = $CurHeight;
//Set the Destination Image path with Random Name
$thumb_DestRandImageName    = $Thumb.$RandomNumber.'.'.$ImageExt; //Thumb name
$DestRandImageName          = $DestinationDirectory.$RandomNumber.'.'.$ImageExt; //Name for Big Image
//Resize image to our Specified Size by calling our resizeImage function.
if(resizeImage($CurWidth,$CurHeight,$BigImageMaxWidth,$BigImageMaxHeight,$DestRandImageName,$CreatedImage))
{
    //Create Thumbnail for the Image
    resizeImage($CurWidth,$CurHeight,$ThumbMaxWidth,$ThumbMaxHeight,$thumb_DestRandImageName,$CreatedImage);
    //respond with our images
    echo '<table width="100%" border="0" cellpadding="4" cellspacing="0">
        <tr><td align="center"><img src="gallery/'.$RandomNumber.'.'.$ImageExt.'" alt="Resized Image"></td></tr></table>';
}else{
    die('Resize Error'); //output error
}

}