Compress a PPTX or POTX file, converting all PNG/TIFF images to lossy JPEGs.
When copy-pasting images to PowerPoint presentations, these sometimes get inserted as lossless versions, blowing up the size of the presentation.
This script takes all PNG or TIFF images part of the presentation which are larger than a given threshold (1 MiB by default), converts them to a lossy JPEG variant, and creates a new PPTX file.
PNGs containing transparency can be skipped to prevent graphics issues. Normally their transparent parts are replaced with white (although you can choose another color).
- Operating system: macOS or Linux
- Note: Under Linux, you need LibreOffice installed to convert embedded EMF files
- Python 3.8 or higher
- ImageMagick's
magickcommands (magick convertandmagick identify) - Optionally:
ffmpegfor media files, and
Under Ubuntu, get ImageMagick via:
apt install imagemagick
Under macOS, install it with Homebrew:
brew install imagemagick
For ffmpeg, use the static builds from ffmpeg.org.
Via pip:
pip3 install --user compress-pptx
Call compress-pptx and point it to a PPTX or POTX file. It'll compress the images and output another compressed file next to it.
For more options, see the -h output:
usage: compress-pptx [-h] [-o OUTPUT] [-s SIZE] [-q QUALITY] [-t TRANSPARENCY]
[-k] [-v] [-f] [-m] [-j] [-l] [--num-cpus NUM_CPUS]
input
positional arguments:
input
options:
-h, --help show this help message and exit
-o OUTPUT, --output OUTPUT
Output file (default: None)
-s SIZE, --size SIZE Minimum size threshold in bytes. Also accepts the
suffixes k/M/G or KiB/MiB/GiB (default: 1MiB)
-q QUALITY, --quality QUALITY
JPEG output quality (0-100) (default: 85)
-crf Video Compression Level 0-51 where 0 is no compression Defaults to 30
-ir Max dimension (width or height) for images. Defaults to 1920
-vr Max dimension (width or height) for video. Defaults to 1280
-t TRANSPARENCY, --transparency TRANSPARENCY
Replace transparency with color (default: white)
-k, --skip-transparent-images
Skip converting transparent images at all (default:
False)
-v, --verbose Show additional info (default: False)
-f, --force Force overwriting output file (default: False)
-m, --compress-media Compress other media types such as audio and video
(requires ffmpeg) (default: False)
-j, --recompress-jpeg
Recompress jpeg images (default: False)
-l, --use-libreoffice
Use LibreOffice to compress EMF files (only way to
compress EMF files under Linux) (default: False)
--num-cpus NUM_CPUS Number of CPUs to use (default: all available CPUs)
Compress all images and video over 512k, keep images under 1920px, 95 quality, keep videos under 1280, 30 quality
compress-pptx -m -j -s=512k -ir=1920 -q=95 -vr=1280 -crf=30 pptx/input_file.pptx
There's an unmaintained Bash version under bash/compress-pptx.sh.
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MIT License
Copyright (c) 2021-2023 Werner Robitza
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.