Compatibility with Media / Media Gallery

This can be made compatible with Media and Media Gallery with a simple addition to masonry_formatter_field_types().

/**
 * Get a list of supported field types and their formatters.
 *
 * @return
 *   An associative array where the keys are field types and the values are
 *   arrays of formatter type names.
 */
function masonry_formatter_field_types() {
  return array(
    'image' => array(
      'colorbox',
      'image',
    ),
    'text_long' => array(
      'text_default',
      'text_plain',
      'text_trimmed',
    ),
    'text_with_summary' => array(
      'text_default',
      'text_plain',
      'text_summary_or_trimmed',
      'text_trimmed',
    ),
    'media' => array(
      'media',
      'media_gallery',
    ),
  );
}

You'll also need to make some CSS modifications to override Media Gallery's attempts to organize field items in to columns and rows. An example of my set up:

  #zone-content .node-media-gallery .field-name-media-gallery-media .field-item {
    margin: 0; }
    #zone-content .node-media-gallery .field-name-media-gallery-media .field-item.masonry-brick {
      width: 230px !important; }

Settings at admin/structure/types/manage/media-gallery/display/full

File view mode: Gallery thumbnail
Masonry: Enabled
Column width: 230 px
Animations: Enabled
Duration: 500 ms
Resizable: Yes
Center grid: Yes
Gutter width: 0 px
RTL layout: No

Voila! Looks great.