<form action="#" method="post">
                <select name="galleryid">
                    <option value="schetsen">Schetsen & Plannen</option>
                    <option value="gyproc">Gyproc & Pleisterwerken</option>
                    <option value="plafond">Plafond, Muur & Vloerafwerking</option>
                    <option value="schrijn">Schrijn, Meubel & Timmerwerk</option>
                </select>
               `<input type="submit" name="submit" value="refresh">
 </form>

<?php
            include "connect.php";
            $rd=rand();
            if(isset($_FILES['files'])){
                $errors= array();
                foreach($_FILES['files']['tmp_name'] as $key => $tmp_name){
                    $file_name = $key.$rd.$_FILES['files']['name'][$key];
                    $file_size =$_FILES['files']['size'][$key];
                    $file_tmp =$_FILES['files']['tmp_name'][$key];
                    $file_type=$_FILES['files']['type'][$key];
                    if($file_size > 2097152){
                     $errors[]='File size must be less than 2 MB';
                 }
                 $query="INSERT INTO tbl_images(`id`,`imgname`,`imgtype`,`imgsize`,`gallery_id`) VALUES('','$file_name','$file_type','$file_size','$_POST['galleryid']')";