Question 1

How do I use oxipng in a Docker container?

Accepted Answer

Run the Docker image from ghcr.io/oxipng/oxipng, mount your working directory, and pass commands like 'docker run --rm -v $(pwd):/work ghcr.io/oxipng/oxipng -o 4 /work/file.png'. This is ideal for CI/CD pipelines or isolated environments.

Question 2

Is oxipng faster than optipng?

Accepted Answer

Yes, oxipng is multithreaded, allowing it to process images much faster on multi-core systems, while optipng is single-threaded. However, oxipng is not a drop-in replacement, so check the manual for compatibility.

Question 3

What does lossless compression mean for PNG files?

Accepted Answer

Lossless compression reduces file size without altering visual quality or any image data, preserving all pixels exactly. Oxipng achieves this through algorithms like refiltering and recompression, as noted in the README.

Question 4

Can oxipng fully optimize animated PNGs?

Accepted Answer

No, oxipng has limited APNG support—it can optimize alpha and recompress frames, but transformations are disabled. For comprehensive APNG optimization, use a dedicated tool like apngopt first, as advised in the README.

Question 5

How to integrate oxipng into a Git pre-commit hook?

Accepted Answer

Add a configuration in .pre-commit-config.yaml with the oxipng repo URL and specify hooks with arguments like optimization level 4 and safe metadata stripping. This automates PNG optimization before commits, improving workflow efficiency.

Question 6

What are the trade-offs of higher optimization levels in oxipng?

Accepted Answer

Higher levels (e.g., -o 6) offer better compression but are slower and have diminishing returns. Since oxipng isn't brute-force, they don't guarantee the smallest file, so balance speed and compression based on your needs.

oxipng

What is oxipng?

Overview

Use Cases

Best For

Related Projects

Found a gem we're missing?

Not Ideal For

Pros & Cons

Pros

Cons

Open Source Alternative To

Frequently Asked Questions