title: r - aligning x-axis image and base plot
body: <p>When I try to align an image plot with a xy plot by their x-axis there is a small misalignment between the x-values. Can't figure out how to get rid of it!
  Notice the misalignment of the vertical lines from the bottom plot with the x-axis on the top plot.</p>
  
  <pre><code>par(mfrow=c(2,1))
  par(mar=c(0,5,5,5))
  image(x=1:100,z=replicate(10, rnorm(100)))
  par(mar=c(5,5,0,5))
  par(xaxs="i")
  plot(1:100,rnorm(100))
  abline(v=1:100)
  </code></pre>
  
  <p>Gurus, help!! Thank you!!</p>
  
  <p>PS: Could not figure it out with the post "plot-time-series-and-image-in-r-so-that-x-axis-labels-line-up-perfectly", still having issues!</p>