為電子郵件、網頁或純粹為了節省空間而縮小圖片的檔案大小。這個工具會壓縮 JPG 和 PNG，並轉換為更小的格式。
它在你瀏覽器中本地執行，因此你的圖片永遠不會離開你的裝置。
如何使用此工具
新增你的圖片
將任何圖片拖曳到工具上，或選擇一個檔案。
選擇輸出品質
已預先選取 JPG，以達到最佳的全面縮小效果。較低的品質 = 較小的檔案。
比較大小
比較檢視會精確顯示你節省了多少。
下載
下載你更小的圖片。
本節目前僅提供英文版本。
Work out where the bytes are going first
Reducing an image file is easier if you know what is making it large. In practice it is almost always one of three things: too many pixels, too much quality, or a format that is wrong for the content.
Check the pixel dimensions before anything else. If a photograph is 4000 pixels wide and will be displayed at 800, you can cut roughly 85% of the data with no visible difference at all — more than any compressor setting will find.
The levers, in order of how much they help
| Lever | Typical saving | Cost |
|---|---|---|
| Resize to the displayed dimensions | 50–90% | None if displayed at that size |
| Move to a modern format (WebP, AVIF) | 25–60% | Needs a fallback for old browsers |
| Lower the quality setting | 20–60% | Visible artefacts if pushed too far |
| Lossless optimisation | 5–30% | None at all |
| Strip metadata (EXIF, thumbnails) | 1–5% | You may want the location and camera data |
A sequence that works
- Crop to what you actually need — unused edges are pure cost.
- Resize to the largest size it will be displayed at, doubled for high-DPI screens.
- Choose the format for the content: WebP or AVIF for photographs, lossless WebP for screenshots and line art.
- Compress at a quality you have looked at, then check the small details at 100% zoom.
- Keep the original. Every step above is one-way.
The mistake to avoid
Converting a JPEG to PNG to "reduce size" does the opposite — PNG will be several times larger, and it cannot recover the detail the JPEG already discarded. Lossless formats only ever make a photograph bigger. Move toward lossy formats for photographs and lossless ones for graphics, never the other way around.
常見問題
讓圖片變小的最快方法是什麼？
以合理的品質重新編碼為 JPG 或 WebP。這一步就能移除大部分多餘的大小。
我可以把圖片縮到多小？
大多數圖片可以縮小 50–80%。極限在於你開始注意到品質損失的地方。
這是永遠免費的嗎？
是的 — 免費、無限量、無需註冊帳號。