在不损失任何质量的情况下压缩 PNG 文件。此工具使用无损优化，移除 PNG 编码中的冗余数据，从而获得更小的文件，且输出与原始像素完全一致。
它完全免费，并在您的浏览器中本地运行。
如何使用此工具
添加 PNG
拖放您的 PNG，或从您的文件中选择。
无损 PNG 已默认选中
输出已设置为无损 PNG。保持默认质量，以确保每个像素都与原图一致。
查看节省空间
工具会在压缩后的大小旁边显示原始大小。
下载
下载您无损压缩后的 PNG。
本节目前仅提供英文版本。
What "lossless PNG compression" actually does
Lossless compression does not touch a single pixel. It reduces the file by encoding the same image data more cleverly — choosing better PNG filter types per scanline, and applying a stronger DEFLATE pass over the result. Every pixel of the output is identical to the input, byte for byte after decoding.
Typical savings are 10–30% for photographic PNGs and rather less for images that are already well optimised, because a PNG that has been through a good encoder once has little redundancy left to find.
How to tell it worked
Compare file sizes, not pixels. If the output is smaller and the image looks identical at 100% zoom, it worked. Because the process is lossless, there is no quality slider to worry about and no such thing as "too aggressive" — the only variable is how long the encoder is allowed to search.
If lossless is not enough
When the file is still too large after lossless optimisation, the choice is between accepting some quality loss and reducing the image itself. In order of how little they hurt: reduce the pixel dimensions to what is actually displayed, reduce the colour depth if the image has few colours, then move to a lossy format such as WebP or JPEG.
Resizing is almost always the bigger win. A 3000-pixel-wide PNG displayed at 800 pixels is wasting more bytes than any encoder setting can recover.
常见问题
PNG 在无损的情况下最多能压缩多少？
通常为 20–50%，具体取决于图片。有大面积纯色区域的图片比噪点较多的照片压缩率更高。
“无损”真的是零质量损失吗？
是的。无损压缩意味着解码后的图像与原始图像逐位完全相同。
为什么我的 PNG 已经很小了？
如果您的 PNG 已经过优化，那么可节省的空间可能所剩无几。该工具始终如实显示结果。