conditional content template based on field submission

// http://www.gravityhelp.com/forums/topic/post-template-condition-based-on-field
// change the number 9 here to your form ID
add_action('gform_post_submission_9', 'conditional_content_template_nine', 10, 2);
function conditional_content_template_nine($entry, $form){
    // $post will contain the full WordPress Post that was created
        $post = get_post($entry['post_id']);
    // $entry[4] is equivalent to your Source field.  Change the number to match your Source field
    // if $entry[4] is not empty, then change the post content
        if($entry[4] <> '') {
                $post->post_content = "$post->post_content <p>Source: <a href='$entry[4]' title='$post->post_title additional information'>$entry[4]</a></p><br class='clear' />";
        // be sure to save the updated post
                wp_update_post($post);
        }
        else { // clear the image with a br
        // I need to clear an image in my post whether or not there is a Source
                $post->post_content = "$post->post_content <br class='clear' />";
                wp_update_post($post);
        }
}