<?php
/* Filter p tags with images */
function kd_filter_ptags_on_images($content) {
    $content = preg_replace('/<p>\s*(<a .*>)?\s*(<img .* \/>)\s*(<\/a>)?\s*<\/p>/iU', '\1\2\3', $content);
    return preg_replace('/<p>\s*(<iframe .*>*.<\/iframe>)\s*<\/p>/iU', '\1', $content);
}
add_filter('acf_the_content', 'kd_filter_ptags_on_images');
add_filter('the_content', 'kd_filter_ptags_on_images');
?>