<?php
$ext = array('jpg', 'gif', 'mpg', 'mpeg', 'png');
$destpath = 'galerije/';

$files = count($_FILES['file']['name']);

for($i = 0; $i < $files; $i++)
{
    if(in_array(pathinfo($_FILES['file']['name'][$i], PATHINFO_EXTENSION), $ext))
    {
        if(move_uploaded_file($_FILES['file']['tmp_name'][$i], $destpath . $_FILES['file']['name'][$i]))
        {
            // Success
        }
        else
        {
            // Failure
        }
    }
    else
    {
        // Extension not allowed
    }
}