compacty

compacty is a configurable command-line tool that compresses files (currently only PNGs, JPEGs, GIFs by default) by running them through multiple compression tools at once, and picking the best result. Inspired by picopt, optimizt, Trimage, and ImageOptim.

...why?

Every tool and every file is unique. Which tool that gives the best compression on one file might be different on another.

compacty was born out of a need in Roblox game development. In Roblox, assets are downloaded every time a player joins a game. Finding the best compression possible is thus crucial to reduce load times. However, manually testing a file against multiple compression tools is tedious. compacty automates this process. It runs your files through multiple compression tools simultaneously using a preset of arguments, and then returning the most optimal compression out of them.

compacty is also my first real shot at learning Go. I enjoyed it.

installation

prerequisites!

[!IMPORTANT] compacty is a meta-tool that runs other compression tools. compacty does not include nor bundle these tools by itself. You must get the tools you wish to use separately and ensure that:

• They're available in your system's PATH, or
• The binary is placed in the same directory as compacty.

The default configuration uses the following tools:

• Efficient Compression Tool (ECT)
• imagemagick
• pingo (for Windows. To run this on Linux and MacOS you would need to install wine)
• oxipng
• pngout
• zopflipng
• pngquant
• jpegoptim
• jpegtran (a JPEG manipulation tool provided by libjpeg, libjpeg-turbo, or mozjpeg)
• gifsicle

from releases

1. Navigate to the Releases page
2. Download the binary appropriate for your operating system (Windows, MacOS, Linux)

from source

Requires Go 1.24.4 or later.

go install github.com/ArrayNone/compacty/cmd/compacty@latest

usage examples

# Run by using a specific preset
compacty --preset=lossy-highquality imageA.png imageB.jpeg

# Run by using the `default-preset` defined in your config file
compacty image.png

# List all of your tools and presets from the config file
compacty --list

# Generate a .tsv report after compressing for further analysis
# The reports are placed to the directory of the first file for each file format
# For example, this command will place the reports as ./report.png.tsv and ./Pictures/report.jpeg.tsv 
compacty --report imageA.png ./Pictures/imageB.jpeg ./Pictures/Photos/imageC.jpeg

# [EXPERIMENTAL] Measure the decoding time for each compression result using Go's native binaries 
# Only PNGs, JPEGs, and GIFs are supported
# (use `--keep-all` to save the results that have the fastest decode time)
compacty --decode-time imageA.png

Run compacty --help to see all available flags.

configuration

compacty uses a config.yaml file that defines tools, presets, etc. On first run, a default configuration will be created in your user's config directory:

• Windows: %APPDATA%\compacty\config.yaml
• Linux: ~/.config/compacty/config.yaml
• macOS: ~/Library/Application Support/compacty/config.yaml

You can see the default configuration at defaultconfig.go. A more complete configuration is available at complete-config.yaml that contains even more tools, ready to be copy-pasted.

In each tool's argument list, you can include (or reuse) arguments from other presets (that are part of the same tool) by using the syntax @preset-name. For example:

pngout:
    description: Lossless PNG compressor. http://www.advsys.net/ken/utils.html
    command: pngout
    platform: [windows, darwin, linux]
    supported-formats: [image/png]
    output-mode: input-output
    arguments:
      default-args: ["-force", "-y"]
      lossless-loweffort: ["@default-args", "-s3"]
      lossless-higheffort: ["@default-args", "-s1"]
      lossless-maxbrute: ["@default-args", "-s0"]
      ...

During runtime, lossless-loweffort will be resolved to ["-force", "-y", "-s3"], lossless-higheffort will be resolved to ["-force", "-y", "-s1"], and so on. This is pretty handy to deduplicate flags that are there for setup (for example: forcing the tools to overwrite files), but can also be used to mix-and-match arguments. Note that circular includes are not allowed.

Your config.yaml will be validated on startup to check for inconsistencies and potential problems. See Validate() in config.go for all checks.

licensing

compacty is licensed under the MIT License. See the LICENSE file for more information.