無損高壓縮比
先進演算法在肉眼無對差的前提下將圖片體積壓縮60～85%，網站載入與儲存成本大幅降低。
100KB is the sweet spot. It is the largest of the common form limits and the smallest target that a typical phone photo can reach at its original dimensions, which means you usually get there without resizing anything.
A 12-megapixel phone photo straight from the camera is usually 3 to 5MB. Getting it to 100KB is a reduction of roughly 97 percent, which sounds impossible and is not: photographs are full of smooth areas that compress extremely well. The result will not survive being printed or cropped in hard, but on a screen at normal viewing size it holds up. This is the reason 100KB, not 50KB, is the number to reach for when a form does not force your hand.
Unlike the 20KB page, the default advice here is to keep your original dimensions. Resizing on top of a 100KB target usually costs you sharpness you did not need to give up.
無需專業技術知識，免費快速的線上圖片處理工具，電腦手機全設備均可使用
我們在每個細節都做到極致，用技術保障每一次處理
Below 100KB every additional kilobyte you remove costs visible quality, because the encoder has already spent the easy savings. Above 100KB the savings come almost free. That makes 100KB the point where the trade-off changes character, which is why it turns up both as a form limit and as a web performance guideline for people who have never seen a government form.
If you are compressing for a website rather than a form, 100KB per image is a reasonable budget for a full-width photograph and generous for anything smaller. Hitting it consistently across a page does more for load time than any single heroic optimisation.
We do not resize your image and we do not convert it to a different format. The target is reached by binary-searching the encoder quality: we encode, measure, adjust and encode again until the result lands just under your number. Because this runs server-side with the real encoders (pngquant, cwebp, gifsicle, libjpeg) rather than a browser canvas, it keeps searching further down than an in-browser tool can before giving up. Target mode is available for JPG, PNG, WebP, GIF, HEIC, JXL, JP2 and JXR; other formats fall back to standard quality-based compression.