title: hierarchical cluster labeling with plots
body: <p>I have a distance matrix for ~20 elements, which I am using to do hierarchical clustering in R.  Is there a way to label elements with a plot or a picture instead of just numbers, characters, etc?</p>
  
  <p>So, instead of the leaf nodes having numbers, it'd have small plots or pictures.</p>
  
  <p>Here is why I'm interested in this functionality.  I have 2-D scatterplots like these (color indicates density)</p>
  
  <p><a href="http://www.pnas.org/content/108/51/20455/F2.large.jpg" rel="nofollow">http://www.pnas.org/content/108/51/20455/F2.large.jpg</a>   (Note that this is not my own data)</p>
  
  <p>I have to analyze hundreds of such 2-D scatter plots, and am trying out various distance metrics which I'm feeding on to hclust.  The idea is to quickly (albeit roughly) cluster the 2-D plots to figure out the larger patterns, so we can minimize the number of time-consuming, follow-up experiments.  Hence, it'll be ideal to label the dendrogram leaves with the appropriate 2-D plots.</p>