Here is a filter that can be adjusted by field type and field name. You can adjust the HTML output as needed.
<?php
// change the field type to the type
// of field you want this run on
// use priority of 1 for before field
// use priority of 20 for before field
add_action('acf/render_field/type=url', 'field_name_render_url_image', 20, 1);
// change the function name to something unique
function field_name_render_url_image($field) {
// change $field name to
// the field to add the image to
$field_name = 'the_field_name';
if ($field['_name'] != $field_name) {
// not our field
return;
}
// uncomment this if you want to see value of $field
//echo '<pre>'; print_r($field); echo '</pre>';
// get the post id
global $post;
$post_id = $post->ID;
// get the current value of the field
// using get_post_meta to avoid confilcts
$url = get_post_meta($post_id, $field_name, true);
if (!$url) {
// nothing has been entered
?><p>Enter a URL and Update to View.</p><?php
return;
}
// make sure the url is an image
// alter regex to change allowed image extensions
if (!preg_match('/\.(jpg|jpeg|png|gif)$/i', $url)) {
// not an image we want to allow
?><p>The Entered is Not A Valid Image URL. Enter a Valid Image URL and Update to View.</p><?php
return;
}
// if we get here then show the image
?>
<img src="<?php echo $url; ?>" />
<?php
} // end function field_name_render_url_image
?>
