Use ImageMagick when dvipng is not available in latex plugin
Problem
dvipng is hard to compile under FreeBSD
Analysis
We could use convert instead of dvipng
Enhancement recommendation
I wrote a small patch to make the latex plugin use the 'convert' command, since it's not that easy to compile dvipng on my FreeBSD system, especially to a TexLive user (no standalone libkpathsea). I omitted the fore/background info, put preserved the DPI and tight functions in the patch. If we accept it, the document string needs to be changed, also.