convert pdf to png

[Diez B. Roggisch]

> Seeing these options, I think it is much better to serve the PDFs
> directly, it's very simple, and very efficient on the server. If
> you're afraid that not everyone have PDF readers, direct them to
> Adobe's site or serve the installation files on the server. The
> installation for the reader is a one-off download, so it should only
> choke the server for the first several weeks.

AFAIK the OP wants to render previews for display on the site - 
certainly a nice feature.

Diez