docuent need for mhchem.sty

diff --git a/doc/plugins/teximg.mdwn b/doc/plugins/teximg.mdwn
index 5c35aa2e8b923ed4f3dfb618af559422466223d9..588bf540777907d506aa7ff5cd90c27a1e06adab 100644 (file)
--- a/doc/plugins/teximg.mdwn
+++ b/doc/plugins/teximg.mdwn
@@ -3,6 +3,10 @@
 
 This plugin renders LaTeX formulas into images.
 
+Of course you will need LaTeX installed for this to work. The plugin
+also uses mhchem.sty, which in Debian is in the texlive-science package and
+may not be part of a regular texlive installation.
+
 ## examples
 
        \[[teximg code="\ce{[Cu(NH3)3]^{2+}}"]]