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function custom_slider() {
	$args = array(
		'name'				=> 'homepage',
		'post_type'			=> 'slider',
		'posts_per_page'	=>	1
	);

	$posts = get_posts($args);
	if ($posts) {
		foreach ($posts as $post) {
			setup_postdata($post);
			if (have_rows('slider_images')) {
				while (have_rows('slider_images')) {
					the_row();
					$img = get_sub_field('slider_image');
					$link = get_sub_field('slider_link');

					if (!empty($link)) {
						echo sprintf('<a href="%s"><img src="%s" /></a>', $link, $img['url']);
					} else {
						echo sprintf('<img src="%s" />', $img['url']);
					}
				}
			} else { echo "Could not find slider images."; }
		}
		wp_reset_postdata();
	} else { echo "Could not find slider."; }
}