Please help me found a fix

Hello my friends,

Im here to request your help fixing 2 littleee things
I have an upload page in my website, where my users can send their photos directly to my website. But I need to fix this:

1- When someone uploads a big photo, the image brokes my layout...
I need to automatically resize the uploaded image with a limit of 800px width. It is possible in the code below? How?

2- When they send the photos, the date will be saved in my database, but I need also the time... It is possible in the code below? How?

<?
   
    include("library/globals.php");
    $dbc=mysql_connect($host,$username,$password) or die('Unable to connect to the database...');
    mysql_select_db($dbname) or die('Unable to select the database...');
   
    if(isset($_POST['submt']))
    {
        $name=$_POST['name'];
        $country=$_POST['country'];
        $email=$_POST['email'];
        $picture=$_FILES['picture']['name'];
        $comment=$_POST['comment'];
           
        $arr=explode('.',$picture);
        $img=date('ymdhis').".".$arr[1];
        $dest="uploaded/".$img;
        $dt=date('Y/m/d');
        $cur_dt=date('Y-m-d');
        $val1=move_uploaded_file($_FILES['picture']['tmp_name'],$dest);
        if($val1)
        {
            $source_img=$dest;
            $watermark = imagecreatefrompng('images/logo.png'); 
            $watermark_width = imagesx($watermark);
            $watermark_height = imagesy($watermark);
            $image = imagecreatetruecolor($watermark_width, $watermark_height); 
            $image = imagecreatefromjpeg($source_img); 
            $size = getimagesize($source_img); 
            $dest_x = $size[0] - $watermark_width - 2; 
            $dest_y = $size[1] - $watermark_height - 2; 
            imagecopymerge($image, $watermark, $dest_x, $dest_y, 0, 0, $watermark_width, $watermark_height, 100); 
            imagejpeg($image,$source_img);
               
            $qry="insert into thon_post (`name`,`picture`,`country_name`,`dt`,`email`,`comment`,`start_date`) values('$name','$img','$country','$dt','$email','$comment','$cur_dt')";
            $rs=mysql_query($qry);
            $val2=mysql_insert_id();
            $dt=date('Y/m/d');
            $str=$val2."%%".$dt."%%http://www.thongsaroundtheworld.com/conteudo/p.php?id=".$val2."%%0%%\n";
            $fp=fopen('ccount/clicks.txt',"a");
            fwrite($fp,$str);
            fclose($fp);
            if($val2>0)
            {
?>
                <script language="javascript" type="text/javascript">
                    alert('Congratulations! Your request is successfully looged in our server.\nWhen we will approve it, it will be displayed in our website.');
                    //window.location.href='upload.php';
                    window.close();
                </script>
<?
            }
        }
    }
?>

PHP:

Help

 

1. You need write function Resize image

 

Can you help me with that?