diff --git a/HACKING b/HACKING
index a46d09792c362fcd431298644ce74fe7a54a6791..39ed1da3f3eaef230cce7eff00c7da5de0c1f3c9 100644
--- a/HACKING
+++ b/HACKING
@@ -34,6 +34,7 @@ since the generated files they produce are distributed.)
     liblocale-gettext-perl or p5-locale-gettext in your distribution)
   A complete LaTeX distribution, including latexmk and extra fonts
     like dsfont.sty.
+  ImageMagick
   Python >= 3.3, IPython >= 2.3
   GraphViz