离线 · 无上传 · 浏览器本地完成Offline · no uploads · runs in the browser
PNG 转 WebP——本地批量压体积，质量与目标大小可调PNG to WebP locally — batch it, tune quality or target size
同一张图，WebP 常常比 PNG 小一大截，而透明通道仍在。这里没有上传：解码、重编码、体积控制都发生在你自己的标签页里。质量参数与目标体积的处理顺序是有讲究的——先沿质量阶梯往下试，质量已经到底还够不着目标，才开始缩边；所以「目标 200 KB」是一个追着去的上限，不是保证值，细节写在下面。The same picture often shrinks a lot as WebP while keeping its alpha channel. Nothing is uploaded here: decoding, re-encoding and size control all happen in your own tab. The order of operations matters and is deliberate — the encoder walks the quality ladder first, and only when quality has bottomed out without reaching the target does it start giving up pixels. So “target 200 KB” is a ceiling being chased, not a promise, and the details are below.
这条链路怎么走How the route runs
PNGPNG WebPWebP
共 1 步，由扩展的路径搜索自动选出，中间产物不落盘。1 step, chosen by the extension's own path search; intermediate results never touch the disk.
会保留什么What carries over
- 透明通道与 Alpha：WebP 编码保留 PNG 的半透明信息The alpha channel: WebP keeps what PNG carried, translucency included
- 质量档（40%–90%）与目标体积（20 KB–2 MB）在输出参数面板里选，两者只在链路末尾那次编码生效Quality steps from 40% to 90% and target sizes from 20 KB to 2 MB, chosen in the output panel and applied only at the encoding step at the end of the route
- 最长边可先缩到 800–4096 px 之间；编码器另有 8192 px 硬上限，超过就先缩而不是静默裁切A longest edge of 800–4096 px to downscale to, with a hard 8192 px encoder ceiling behind it — oversized renders shrink rather than clip
- 同一批可以同时出 JPEG 与 PNG，三种可写格式的质量档共享同一套语义The same batch can also emit JPEG and PNG, the three writable formats sharing one quality vocabulary
如实说明的限制What it does not do
- 目标体积是「追得上就追」：质量降到底仍不够时会继续缩像素，但极小的目标可能到不了，产物只保证不超过约束能达到的最小值A target size is chased, not guaranteed: once quality bottoms out the encoder starts shedding pixels, and a very small target may still be unreachable
- 有损编码不可逆：WebP / JPEG 反复转手的每一次都在丢信息，请始终从原始 PNG 出发Lossy is not reversible — every extra WebP or JPEG handoff discards more. Always start from the original PNG
- 动图取首帧：GIF 会给出「只保留第一帧」那句提示，APNG 不会——实测一份 Pillow 生成、可被浏览器解出的双帧 APNG 成功转出静帧 WebP，界面无任何丢帧提示（帧检查只对 GIF 生效，`utils/core/animated-image.ts:16`）；BMP / GIF / SVG 不能被浏览器编码，所以只能作为输入Animations yield their first frame, and only a GIF says so: measured with a Pillow-written two-frame APNG the browser decodes normally, this route produced a still WebP with no frame-loss notice, because the check covers GIF only (`utils/core/animated-image.ts:16`). BMP, GIF and SVG cannot be encoded by a browser, so they are input-only
- 不做 OCR、不做智能裁剪、不替你去网上取图No OCR, no smart crop, and it never fetches an image for you
实操提示Working with it
- 一批最多 200 张、单张上限 100 MB；结果可一次打包成 ZIPUp to 200 images per batch and 100 MB each, downloadable as one ZIP
- 输出参数在界面里设置后会被记住，同一批的所有图片共用一次设置The output settings persist between runs and apply to every file in the batch from one read
常见问题Questions people actually ask
为什么设了目标大小还是超了？Why did it still miss my target size?
因为可用的杠杆有尽头：质量档走到最低、边长缩到上限以内仍达不到时，产物就是当前最小可行结果。想要更小，得改图像本身（尺寸、色数、内容复杂度）。Because the available levers bottom out: if the lowest quality and the smallest permitted edge still exceed the target, the result is the smallest thing that still decodes correctly. Below that you have to change the image itself — dimensions, colour count, or how complex the content is.
WebP 都支持吗？Is WebP supported everywhere?
现代浏览器与主流系统都支持，但把 WebP 当交付格式前请确认接收方环境；要「任何设备都能开」，PNG 仍是更安全的那个。Current browsers and mainstream systems handle it, but check the recipient before shipping WebP; where “opens anywhere” is the requirement, PNG remains the safer answer.
能一次转很多张吗？Can I do many at once?
能，一批最多 200 张，混合来源格式也行；单个文件失败只报该文件，其余继续。Yes — up to 200 images in one run, mixed sources included, and one bad file reports only itself while the batch continues.
不需要账号，也不需要联网：装好扩展后点图标，在新标签页里打开工作台，文件从磁盘直接选。No account and no network: install the extension, click its icon, and the workbench opens in a new tab reading straight off your disk.
从 Chrome 应用商店安装Install from the Chrome Web Store 安装步骤Install steps GitHub 源码Source on GitHub
要把它压到指定体积？Need it under a target size? The 图片压缩工具image compressor可以在浏览器里重编码 PNG / JPEG / WebP。 re-encodes PNG / JPEG / WebP in the browser.