Image ACF in Current Author Page

Hello
I need help on one problem. I created a Image Custom field in the User profile. In the Author Page, I can’t succeed displaying the image. I tried many things without success. This is my code now :

<?php get_header(); ?>

<?php
$curauth = (isset($_GET['author_name'])) ? get_user_by('slug', $author_name) : get_userdata(intval($author));
?>
			<div id="primary">
			<div id="content" role="main">
			<div id="profil">
			<p>Etage <?php echo $curauth->etage; ?> Atelier <?php echo $curauth->numero_datelier; ?></p>
			<h1 class="entry-title"><p><?php echo $curauth->display_name; ?></p></h1>
			<p><?php echo $curauth->designation; ?></p>
		<p><?php echo $curauth->description; ?></p>

<?php
$author_id = get_the_author_meta( 'ID' );
$image_resident = get_field('image_resident', 'user_'. $author_id ); // image field, return type = "Image Object"

?>
<img src="<?php echo $image_resident['url']; ?>" alt="<?php echo $image_resident['alt']; ?>" />

			<p><a>user_url; ?>"><?php echo $curauth->user_url; ?></a></p>
			<p><a>user_email; ?>"><?php echo $curauth->user_email; ?></a></p>

Everything works (some are custom fields) except the Image.
Any idea ?
Thank you.
f