PHP и input, смена изображений

<?php 
        $dir = "../../images/"; 
        $images = scandir($dir);
        $images = preg_grep('/\\.(?:png|Png|PNG|ico|gif|jpe?g)$/', $images);
    ?>

<form method="POST" action="adminka_page.php?action=<?=$_GET['action']?>&id_ad=<?=$_GET['id_ad']?>" class="add_form" > 
<div id="img">
//для каждой картинки свой radio
<?php foreach ($images as $image):?>
 
    <input type="radio" name="image" value="<?=$dir.$image?>">
    <img src="<?=$dir.$image?>">
<?php endforeach; ?>
</div>
//и собственно сама проблема
<?php 
    if (!empty($image)){
        $image = $advantage['image'];   
        var_dump($advantage['image']);
        var_dump($dir.$image);
     ?>
     <input type="radio" name="image" value="<?=$advantage['image']?>" checked >
     <?php
    }else{
    ?>
    <input type="radio" name="image" value="<?=$dir.$image?>">
    <?php 
        }
    ?>
        <input type="text" name="head_ad" maxlength="27" value="<?=$advantage['head_ad'] ?>" placeholder="Заголовок" autofocus required class="form_item">
        <div class="admin_img_add form_item"> <img src="<?='../../'.$advantage['image']?>"> </div>
        <textarea class = "form_item description_it" maxlength="127" name="description_ad" required><?=$advantage['description_ad']?></textarea>
        <input type="submit" value="Добавить" class="btn_link">
    </form>