You could convert your HTML to postscript via HTMLDOC (GPL) and then use Ghostscript.pm (Perl API for Ghostscript) to convert to a ppm. Then convert your ppm to a GIF, which can then be loaded into Image::Magick.

Here is a shell script showing how ghostscript converts a postscript file to a ppm on the command line, you could probably simulate these actions using Ghostscript.pm:

#! /bin/sh
#    pstogif
#
# Call it by putting the .ps file name as first argument
# but without the ".ps" extension.  
# Ex:  for "Intro_Tbl.ps" use "pstogif Intro_Tbl"
#
gs -r72x72  -sDEVICE=ppmraw -sOutputFile=$1.ppm << endinput
   ($1.ps) run
endinput
 
pnmcrop < $1.ppm | ppmtogif > $1.gif
[download]

...This requires both GhostScript and pbmplus to work.

HTH. :-)

--
hiseldl
What time is it? It's Camel Time!