Batch-Export PowerPoint Slides to Images Programmatically

unoconv is a tool to "convert between any document format supported by OpenOffice," available to install via Homebrew on macOS. You can convert, for instance, ppt files to png images (or to a multi-page PDF files) by running a command with this command-line interface program. The project is open source and you can browse its code on GitHub.

Install unoconv with Homebrew

brew install unoconv

Common issues: LibreOffice not found on your system

I ran into this issue when I first ran the unoconv command.

unoconv
# unoconv: Cannot find a suitable office installation on your system.
# ERROR: Please locate your office installation and send your feedback to:
#        http://github.com/dagwieers/unoconv/issues

That's because unoconv can't find libreoffice. You can install its Homebrew Cask.

brew install --cask libreoffice

After doing that, unoconv can find the libreoffice installation.

unoconv
# unoconv: you have to provide a filename or url as argument
# Try `unoconv -h' for more information.

Export PowerPoint Slides to PDF

unoconv slides.pptx -f pdf

Convert PDF to PNG or JPG Images

Even though you can directly export a PowerPoint presentation to JPEG or PNG format, unoconv exports only the first page by default.

You can use ImageMagick's convert tool to rasterize the PDF pages as images.

convert -density 300 slides.pdf image%d.jpg

Batch-convert Presentations to Images

Here's a bash script that will convert all ppt presentations in a folder to jpg images by folders.

# Convert all pptx files to multi-page pdf files
unoconv -f pdf *.pptx

# Loop through pptx files
for f in *.pptx
do
    echo "${f}.."
    mkdir -p ${f}-jpg
    convert -density 20 ${f%.*}.pdf "./${f}-jpg/image%d.jpg"
done

Available formats

You can see the extensive list of supported input and output formats on unoconv's documentation and read more about how to use unoconv in its help manual page or by running unoconv -h.