Super late but support for this request has been added in the latest commit of the [Packery][1] module: [Commit 24856cf on 7.x-1.x by swim: Added imagesLoaded support on per settings basis][2].

Just toggle on/off on the settings page, and read the README.txt for the plugin placement. Here is a quote from the updated README.txt:

> ### ImagesLoaded support
>
For imagesLoaded support please download the plugin from https://github.com/desandro/imagesloaded.  
Place the plugin in the libraries directory at sites/all/libraries/imagesloaded so that the file is at sites/all/libraries/imagesloaded/imagesloaded.pkgd.min.js.


  [1]: https://www.drupal.org/project/packery
  [2]: http://drupalcode.org/project/packery.git/commit/24856cf