Advanced Custom field thumbnail - wordpress

Question

I'm working on a website in wordpress, i'm trying to get the thumbnail from the advanced custom field of a post with this:

<?php while ( have_posts() ) : the_post(); ?>
    <h1><?php the_field('custom_title'); ?></h1>
    <img src="<?php the_field('thumbnail'); ?>" alt="" />
    <p><?php the_content(); ?></p>
<?php endwhile; // end of the loop. ?>

The problem it's that when I load the website, the url the image gets looks like this:

<img src="5, , item_alt2, , , http://portfolio.local/wp-content/uploads/2012/09/item_alt2.jpg, Array">

So, as far as I see, the plugin it's working since looks for the image, but it loads an strange path to it, so it shows like "broken" image.

What i'm doing wrong?

 5, , item_alt2, , , http://portfolio.local/wp-content/uploads/2012/09/item_alt2.jpg, ArrayNULL

Answer 1

Have a look at the docs on Advanced Custom Fields;

http://www.advancedcustomfields.com/docs/field-types/image/

You are returning the value of the custom field as an object as per the example at the bottom;

Array
(
[id] => 540
[alt] => A Movie
[title] => Movie Poster: UP
[caption] => sweet image
[description] => a man and a baloon
[url] => http://localhost:8888/acf/wp-content/uploads/2012/05/up.jpg
[sizes] => Array
    (
        [thumbnail] => http://localhost:8888/acf/wp-content/uploads/2012/05/up-150x150.jpg
        [medium] => http://localhost:8888/acf/wp-content/uploads/2012/05/up-300x119.jpg
        [large] => http://localhost:8888/acf/wp-content/uploads/2012/05/up.jpg
        [post-thumbnail] => http://localhost:8888/acf/wp-content/uploads/2012/05/up.jpg
        [large-feature] => http://localhost:8888/acf/wp-content/uploads/2012/05/up.jpg
        [small-feature] => http://localhost:8888/acf/wp-content/uploads/2012/05/up-500x199.jpg
    )

)