What Is PNG Quantize, and When Should You Use It?
PNG is a lossless format, but one more step decides how small the file actually gets: whether to reduce the number of colors to a smaller palette (quantize). That step is mildly lossy, and it can shave off a meaningful amount of size.
"Lossless format" and "small file" are not the same thing
PNG is lossless, meaning it doesn't discard pixel detail the way JPG does — but that doesn't mean PNG files are naturally small. A PNG with millions of distinct colors (a photo saved as PNG, for example) can be large if every color is recorded exactly pixel by pixel, because lossless compression can only pack the same information more efficiently — it can't drop data out of thin air.
How the presets use this toggle
| Preset | PNG size optimization | Effect |
|---|---|---|
| Max compression | On | Smallest files; color-heavy images may show slight banding |
| Balanced (recommended) | On | A common sweet spot between size and quality |
| High quality | Off | Keeps full color precision; files are noticeably larger |
The "high quality" preset turns this toggle off by default specifically to preserve the most complete color information, at the cost of a larger file.
When to turn this toggle off
For screenshots, icons, flat-color blocks, and UI mockups — content that already has a limited color range — quantization rarely produces a visible difference, so it's safe to leave on. But for gradient skies, carefully color-graded photography, or design deliverables that need professional-grade color precision, quantization can introduce slight banding or color shift, so it's worth turning off or switching to the high-quality preset instead.
- If unsure, test one representative image with the toggle on and off, then zoom in and compare color transitions.
- For deliverables that need exact color fidelity — print-bound images, for instance — turn quantization off outright.
References
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