在不損失任何品質的情況下壓縮 PNG 檔案。這個工具使用無損最佳化，會移除 PNG 編碼中多餘的資料，因此你可以獲得像素完全相同的更小檔案。
它完全免費，且在你的瀏覽器中本地執行。
如何使用此工具
新增你的 PNG
將你的 PNG 拖曳到工具上，或從你的檔案中選擇它。
已預先選取無損 PNG
輸出已設定為無損 PNG。將品質保留在預設值，即可保持每個像素完全相同。
查看節省的空間
工具會顯示你的原始大小，以及壓縮後的大小。
下載
下載你無損壓縮後的 PNG。
本節目前僅提供英文版本。
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.
常見問題
PNG 在無損情況下最多可以壓縮多少？
通常取決於圖片，約可壓縮 20–50%。具有大片平坦區域的圖片比雜訊多的照片壓縮效果更好。
「無損」真的不會損失品質嗎？
是的。無損壓縮代表解碼後的影像與原始影像逐位元完全相同。
為什麼我的 PNG 已經很小了？
如果你的 PNG 已經被最佳化過，可能就沒剩下多少可以節省。工具永遠會顯示真實的結果。