title: How to import local image using knitr for markdown
body: <p>I have an externally created png image in a local directory that I'd like to import to a report using knitr. The ultimate target filetype is html. I have no trouble getting my own figures to appear when I create them with R code, but I'm at a loss what I would have thought was a simpler problem.</p>
  
  <p>While I'm at it, how would I import a figure for which I have a url?</p>