wcdogg/imgsqueeze

Python 3.10+ command line tools to reduce the size of JPEG, PNG, and TIFF.

IMGsqueeze

Python 3.10+ command line tools to reduce the file size of JPEG, PNG, and TIFF files in bulk.

• IMGzlib - Lossless Zlib compression
• IMGquant - Reduce color palette
• IMGdown - Downscale pixel dimensions

I wrote IMGsqueeze for 2 broad use cases:

• Reducing file size while maintaining high visual quality.
• Producing intentionally low-res images for things like product listings (anti-scraping tactic).

Hell No!

• No uploading to a web service. No privacy concerns. No Internet needed.
• No processing limitations like with free services - and even some paid ones.
• No paying for subscription services that include dozens of conversion types you'll never use.

Hell Yeah!

Bulk Processing

• IMGsqueeze tools work on directories.
• Files directly inside a directory are subject to processing.
• Subdirectories are ignored.
• The directory can contain a mix of file formats - no need to pre-sort.
• Non-image files + unsupported image formats are ignored.
• Format is determined by MIME type - and not file extension.

Pillow Options

Because I wrote IMGsqueeze for 2 opposing reasons, the tools offer most of Pillow's built-in options. For example, there's no good use case for a Zlib level below 6, but there's no logic preventing it. Similarly, you can choose which downscaling algorithm to use.

One notable exception is with quantize. While the baked-in Pillow method let's you select an algorithm, it has crappy dither options. Here I decided to force the use of LIBIMAGEQUNT because a) it's by far the best RGB algorithm and b) its method allows full dither control.

Smart Saving

• IMGsqueeze automatically creates a save directory alongside the proc directory.
• The save directory's name reflects the task & settings. This makes it easy to compare different combinations without the hassle of renaming folders or accidentally overwriting the source directory.
• IMGsqueeze is non-destructive - images are copied then processed. Original files are unchanged.
• Filenames are unchanged, so it's easy to update images in existing projects - I hate prefixes and suffixes.

Helpful Logging

• Processing results are written to the terminal and to a task.log inside the save directory.
• Task-level summaries make it easy to spot potential problems - like files that weren't processed or that resulted in a larger file size.
• Image-specific results include pre- and post-processing data for easy comparison and troubleshooting.

VS Code venv

1. Clone repo and open directory in VS Code.
2. In VS Code Bash terminal:

# Create venv - adds folder to project.
py -3 -m venv venv

# Activate venv - no visual confirmation.
venv/Scripts/activate.bat

# Command Palette > Python Select Interpreter > Enter Interpreter Path
# Browse to and select: /project/venv/Scripts/python.exe
# Kill / new Bash terminal.

# Do a sanity check.
which pip3

# Install requirements.
py -m pip install -r requirements.txt --upgrade

Test Directories

This repo contains a test-images directory. Here you can also view sample task.log files.

IMGsqueeze\test-images\jpeg" 
IMGsqueeze\test-images\png"
IMGsqueeze\test-images\tiff"
IMGsqueeze\test-images\other"

IMGzlib

py IMGzlib.py --help

# Default max 9 zlib
py IMGzlib.py "D:\GitHub\IMGsqueeze\test-images\jpeg"

# Options
py IMGzlib.py --zlib 7 "D:\GitHub\IMGsqueeze\test-images\jpeg" 

IMGquant

py IMGquant.py --help

# Default 256 colors, 1.0 dither, 9 zlib
py IMGquant.py "D:\GitHub\IMGsqueeze\test-images\jpeg"

# Options
py IMGquant.py --colors 64 --dither 0.5 --zlib 7 "D:\GitHub\IMGsqueeze\test-images\jpeg"

IMGdown

py IMGdown.py --help

# By width, default LANCZOS, 9 zlib
py IMGdown.py --width 800 "D:\GitHub\IMGsqueeze\test-images\jpeg"

# By height, default LANCZOS, 9 zlib
py IMGdown.py --height 800 "D:\GitHub\IMGsqueeze\test-images\jpeg"

# By width + height, default LANCZOS, 9 zlib
py IMGdown.py --width 800 --height 700 "D:\GitHub\IMGsqueeze\test-images\jpeg"

# By width, BICUBIC, 7 zlib
py IMGdown.py --algo 3 --width 800 --zlib 7 "D:\GitHub\IMGsqueeze\test-images\jpeg"