Q: 桌面截圖、手機截圖 改選 PNG 或存 JPG?
A:
JPEG can produce a smaller file than PNG for photographic (and photo-like) images since it uses a lossy encoding method specifically designed for photographic image data. Using PNG instead of a high-quality JPEG for such images would result in a large increase in filesize (often 5-10 times) with negligible gain in quality.
JPEG 在面對自然影像的時候，由於是採用失真壓縮演算法，因此壓縮率比 PNG 還要大。簡單來說，如果一張 風景照片 你用 JPG 來存，需要 1MB 的話，用 PNG 就要 5MB~10MB，雖然 PNG 檔案較大但是在視覺品質上面並沒有顯著的優越。
PNG is a better choice than JPEG for storing images that contain text, line art, or other images with sharp transitions. Where an image contains both sharp transitions and photographic parts a choice must be made between the large but sharp PNG and a small JPEG with artifacts around sharp transitions. JPEG also does not support transparency.
PNG 在處理包含文字、線條和明顯輪廓的影像 則較 JPG 來的優越，當影像有明顯輪廓邊緣，JPG 的失真演算法在處理這種邊緣上就會產生瑕疵，PNG 採用無失真演算法，因此影像品質較佳。
資料參考自 :
該用 PNG 還是 JPG 來存螢幕截圖
http://brownywalking.blogspot.tw/2008/03/tip-png-jpg.html
[WEB]JPG 、GIF、PNG 三種格式的比較 @ 老周的部落
http://mingwang0824.pixnet.net/blog/post/27833076-%5Bweb%5Djpg-%E3%80%81gif%E3%80%81png-%E4%B8%89%E7%A8%AE%E6%A0%BC%E5%BC%8F%E7%9A%84%E6%AF%94%E8%BC%83
JUST SHARE
沒有留言:
張貼留言