PNGPNG

PNG 是一种无损图像格式——压缩不丢信息，每一次保存都和原图一致。

• 适合：图形、截图、需要透明底的图、要反复改稿的存档。
• 无损阵营：同族的还有 TIFF（可存高位深）与音频里的 FLAC（见 无损与有损）。
• 代价：体积比有损格式大——照片类内容通常不选它交付。
• 和 JPG 的分工：图形与截图 PNG，照片与兼容 JPG（见 JPG）。

PNG is a lossless image format — compression that loses nothing; every save matches the original exactly.

• Made for: graphics, screenshots, images needing transparency, archives you will re-edit.
• The lossless camp: TIFF beside it (stores high bit depth) and FLAC for audio (see Lossless & Lossy).
• The cost: bigger files than lossy formats — photos rarely deliver as PNG.
• Division of labour with JPG: graphics and screenshots PNG, photos and compatibility JPG (see JPG).