免費線上壓縮 JPG 圖片。無論你是要透過電子郵件傳送照片、上傳到網站，還是儲存圖片，更小的 JPG 都能節省時間和頻寬。
這個工具完全在你的瀏覽器中執行，因此你的圖片永遠不會離開你的裝置。
如何使用此工具
新增你的 JPG
將你的 JPG 拖曳到工具上，或選擇一個檔案。
設定品質
已預先選取 JPG。70–80% 的品質可移除大部分可見的偽影，同時大幅縮小檔案大小。
比較並下載
預覽結果，然後下載你壓縮後的 JPG。
本節目前僅提供英文版本。
What you are actually trading away
A JPEG has already been compressed once. Compressing it again re-encodes an image that has already lost detail, so the artefacts compound: what looked clean at quality 85 will look noticeably softer after a second pass at 70. Each additional pass costs more than the last.
This is why the quality slider on a re-compression tool behaves differently from the one in a camera or an editor. In an editor you are encoding from original data. Here you are encoding a copy of a copy.
Choosing a quality setting
| Setting | Typical use | What it costs |
|---|---|---|
| 85–95 | Archive, print preparation, images that will be edited again | Barely any saving; near-original size |
| 70–85 | Web delivery, hero images, photographs viewed on screen | Slight softening, generally invisible at normal size |
| 50–70 | Thumbnails, previews, email attachments | Visible artefacts on close inspection |
| Below 50 | Only when size is the overriding constraint | Blocking and banding that most people will notice |
Getting a better result
- Compress once, from the original, rather than repeatedly from the JPEG.
- Resize before compressing — fewer pixels always beats a harder encoder setting.
- Keep the original file. Re-compression is one-way.
- If you will compress again later, start from the original then too.
常見問題
我可以把 JPG 壓縮多少？
視來源圖片和你選擇的品質等級而定，通常可以節省 30–70%。
壓縮 JPG 會降低品質嗎？
JPG 壓縮是有損的，但在品質 70–80 時，對網頁用途而言差異通常是看不見的。
有任何限制嗎？
沒有次數限制、沒有帳號、沒有浮水印。想壓縮多少圖片都可以。