Hi Finaly create the solution with a mix of various answers !
I’ve used :
<?php
$image = get_field('photo_2');
$image_url = $image['sizes']['medium'];
if( !empty($image) ): ?>
<a class="fancybox" href="<?php echo $image['url']; ?>">
<img src="<?php echo $image_url; ?>" alt="" />
</a>
<?php endif; ?>
Hi @gab1982 did you find a way not to regenerate the css file each time ?
Thanks a lot