I Wrote a Rust Image Compressor That Survives WeChat's Brutal Re-Compression

I Wrote a Rust Image Compressor That Survives WeChat's Brutal Re-Compression

If you've ever sent a photo through WeChat and watched it come out looking like it went through a blender, you know the feeling. The colors shift, gradients turn into visible banding, and fine detail just evaporates. Instagram and WhatsApp do the same thing, just with different thresholds.

I got annoyed enough to actually dig into what these platforms do to images, and then I built a tool to fight back. It's written in Rust, uses mozjpeg, keeps full 4:4:4 chroma, and — the part I'm personally most happy with — it exposes a clean JSON interface so AI agents can drive it directly.

Here's the whole story: what the platforms are actually doing, what I built to counter it, and why I bothered with Rust.

What platforms actually do to your images