Optimize PNG/JPG assets: lossless for docs, lossy for screenshots

[adem4ik]

Image Optimization

Images were optimized using 2 different strategies:

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1. Documentation Images (/static/img/docs/)

Size diff: 6.8 MiB → 5.7 MiB

Approach: Lossless optimization using File Optimizer (images are pixel-identical to the originals).

Rationale:

• Chosen mostly for historical reasons
• These images are already quite small and have their own compression artifacts
• Lossy recompression would produce significantly more artifacts in this case
• Docs pages are visited less frequently, so page loading time is less critical here

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2. Frontpage Screenshots (static/img/screenshots/)

Size diff: 804 KiB → 463 KiB

Approach: Lossy optimization using pngquant, combined with lossless optimization afterwards.

Command used for pngquant:

pngquant --quality=95-100 --speed=1 --strip --skip-if-larger --ext=.png --force *.png

Rationale:

• These images are visible on the front page, so page loading time is critically important
• Upon careful comparison, minor compression artifacts are noticeable on the buttons
• Text and forms remain mostly unchanged
• Given the high resolution of the original images (~3200x2000px), most users won't notice the artifacts

Artifacts example:

[ngosang]

We have to re-do most of the screenshots for the 3.1.0 release. Doing this with images that are going to be removed is wasting space in the git repository.
Maybe you can open a PR improving the documentation about the images? We are using a different software for optimize PNG.
https://github.com/amule-org/amule-org.github.io/blob/main/docs/developer/documentation.md#images

[adem4ik]

@ngosang thanks for the feedback, you can close this PR.

Re: documentation update:

• File Optimizer is a GUI that bundles several tools (including optipng as noted in your link) and picks the best result. It's Windows-only but works well via Wine on Linux. It's easy to use and supports batch optimization. Should I open a PR adding it as an alternative to the command-line optipng in the docs?
• Speaking of pngquant alone, it's not a straightforward tool — it can degrade image quality and requires careful parameter tuning depending on the desired outcome, so I wouldn't recommend it for the docs.