I want to convert PPT to png, or other image formats using Python.
This question has been asked on SO, but essentially recommends running OpenOffice in headless X server, which was an absolute pain last time I used it. (Mostly due to hard to replicate bugs due to OO crashing.)
Is there any other way, (Hopefully using Linux CLI utilities only, and pure Python above them?)
A basic workflow :
convert your ppt to pdf by using a pdf printer from PowerPoint or OpenOffice's built in PDF converter
use ghostscript to convert the pdf to png or other image format (something along the line of gs -dSAFER -dBATCH -dNOPAUSE -sDEVICE=png16m -r100 -sOutputFile=out.png in.pdf)
You can use Python to script this (and pilot OOo / MSPP using Uno / COM), or any script you want.
As far as I know, there is no Python library handling PPT files or converting PDF files to PNG.
As for the OOo crash handling, I would catch Exceptions and attempt a restart of OOo when such event occurs (and probably skip the file, adding it to a list of suspicious files requiring manual processing).
You may find this article http://www.linuxjournal.com/node/1007788 interesting as it provides a class which uses an existing OOo instance to connect or launches one if required in a transparent fashion. It comes with an example of xls -> csv conversion (http://www.linuxjournal.com/content/convert-spreadsheets-csv-files-python-and-pyuno) which can be used as a basis for the conversion you want to attempt.