title: Imagemagick (convert: pixels are not authentic)
body: <p>I have a command-line that outputs an image as intended but gives me an error on completion of <strong>convert: pixels are not authentic</strong>. Why could this be happening? </p>
  
  <p>I am using <em>ImageMagick 6.9.2-8 Q16 x86_64 2015-12-06</em> in <em>Term2</em> on <em>OSX El Capitan</em>.</p>
  
  <p>The command / output / error :</p>
  
  <pre><code>convert -verbose artwork.jpg -resize 1800x \
  \( +clone -gravity center -background white -extent 2000x2000 \) \
  \( -clone 1 displaceY.png -compose displace -define compose:args=0x5% -composite \)  \
  \( -clone 2  -gravity west displaceX.png -compose displace -define compose:args=5x0% -composite \) \
  -delete 0--2 \( +clone alpha.png -compose copy_opacity -composite \) -delete 0 out.png
  
  artwork.jpg JPEG 2952x2124 2952x2124+0+0 8-bit sRGB 911KB 0.000u 0:00.000
  displaceY.png PNG 2000x2000 2000x2000+0+0 8-bit sRGB 109KB 0.000u 0:00.000
  displaceX.png PNG 2400x2400 2400x2400+0+0 8-bit sRGB 104KB 0.000u 0:00.000
  alpha.png PNG 2000x2000 2000x2000+0+0 8-bit sRGB 63.9KB 0.000u 0:00.000
  artwork.jpg=&gt;out.png JPEG 2952x2124=&gt;2000x2000 2000x2000+0+0 8-bit sRGB 572KB 0.000u 0:00.000
  
  convert: pixels are not authentic `artwork.jpg' @ error/cache.c/QueueAuthenticPixelCacheNexus/4017.
  </code></pre>