Use a spinner icon instead of the word "Loading" for thumbnails that are
being processed in the background in a batch upload.
Also use morphdom to update thumbnails so we only update the parts of
the DOM that actually changed.
Components are used to encapsulate common UI widgets used throughout the site. This includes things like comments, tag
lists, post thumbnails, paginators, and other things used repeatedly throughout the site. Components encapsulate a
widget's HTML, CSS, and Javascript together so that all the code for a component is in a single place.