title: How to use an image as a point in ggplot?
body: <p>Is there some way to use a specific small image as a point in a scatterplot with ggplot2.  Ideally I will want to resize the images based on an variable.</p>
  
  <p>Here's an example:</p>
  
  <pre><code>library(ggplot2)
  p &lt;- ggplot(mtcars, aes(wt, mpg))
  p + geom_point(aes(size = qsec, shape = factor(cyl)))
  </code></pre>
  
  <p>So I basically want to know if there is a way to supply a specific image as the shape?</p>