How to disable?

Good question. I hadn’t considered that use case before, but it’s a good one.

try this (in functions.php) and let me know how it works for you:

function picturefill_wp_exclude_by_post_type($post){
  if('post_type_you_want_to_exclude' === $post->post_type){
    remove_filter('the_content', array(Picturefill_WP::get_instance(), 'apply_picturefill_wp_to_the_content'), 11);
  }
}
add_action('the_post', 'picturefill_wp_exclude_by_post_type');

The upcoming version 1.3.0 will include a few new features that will make it easier to use Picturefill.WP on a more conditional basis. I will certainly add this use case to one of the “helper functions” that I plan to bundle with that release.

Thanks very much

Works like a charm! Thanks!