title: location for pic in exams Rnw file
body: <p>I am trying to add a picture with \includegraphics{pic.png} into a question of an .Rnw file from the <a href="https://cran.r-project.org/web/packages/exams/index.html" rel="nofollow noreferrer">exams package</a>.</p>
  
  <p>Something along the lines of: </p>
  
  <pre><code>\begin{question}
  What day is today: \includegraphics{picture.png}
  
  \begin{answerlist}
    \item \Sexpr{questions[1]}
    \item \Sexpr{questions[2]}
    \item \Sexpr{questions[3]}
    \item \Sexpr{questions[4]}
  \end{answerlist}
  
  \end{question}
  </code></pre>
  
  <p>running exams2pdf then </p>
  
  <pre><code>exams2pdf(myexam, n = 1, nsamp = 2, dir = odir, 
                     template = c("my_exam", "solution"), 
                     encoding = 'UTF-8',
                     header = list(
                       Date = "30.05.2017"))
  </code></pre>
  
  <p>gives me: </p>
  
  <pre><code>Error in texi2dvi(out_tex[j], pdf = TRUE, clean = TRUE, quiet = quiet) : 
    Running 'texi2dvi' on 'my_exam1.tex' failed.
  LaTeX errors:
  ! Package pdftex.def Error: File `picture.png' not found.
  </code></pre>
  
  <p>I tried pretty much all the directories the pic could be in but tex2dvi / exams2pdf does not find the png - any advice on that?</p>