使用结果前如何检查？
除文件大小外，也要比较像素尺寸和画质。较小或已优化的图片重新编码后可能更大；更改格式后检查透明区域，JPEG 无法保留透明通道。
Image Compressor可以处理什么？
Image Compressor 用于在浏览器中转换数据或文件，并清楚显示处理结果和限制。 已核对的功能： JPEG, PNG, and WebP input, Quality control, Maximum width 12,000 pixels, Metadata removal.
Choose format by image content
Use JPEG for opaque photographs, PNG for lossless graphics or transparency, and WebP for modern web delivery after checking target-browser support.
如何使用？
- Choose one JPEG, PNG, or WebP file smaller than 30 MB.
- Select output format, quality, and a maximum width up to 12,000 pixels.
- Compress the image, compare exact file sizes, and download the result.
实际输入输出示例
Re-encode a photograph as WebP
输入
photo.jpg, quality 80%, maximum width 1600 px输出
photo-output.webp with measured byte sizeThe browser scales the pixels when necessary and encodes a new WebP file without the source EXIF metadata.
常见错误与修复方法
| 现象 | 可能原因 | 修复方法 |
|---|---|---|
| The file cannot be decoded. | It is damaged, mislabeled, or unsupported by the browser. | Open and export a valid JPEG, PNG, or WebP copy first. |
| The output is larger. | The selected format or quality is less efficient for this image. | Compare WebP or JPEG and reduce quality or dimensions when transparency is not required. |
File size depends on pixels and format
该工具的实际边界： A smaller dimension or lossy format can reduce size, but PNG or a high quality setting can create a larger file. Very large pixel dimensions can exceed device memory.
标准与实现参考
- MDN — Web image formats (opens in a new tab)Compares compression and transparency support.
- MDN — HTMLCanvasElement.toBlob() (opens in a new tab)Documents the browser export API.
关于Image Compressor的常见问题
Are images uploaded?
No. Decoding, canvas rendering, and file creation happen in the current browser tab.
Does compression remove EXIF?
Yes. Canvas re-encoding removes source EXIF and most other metadata.
Why can output be larger?
PNG or a high quality setting can exceed an already optimized source.
更新记录
本次实质更新： Image Compressor: Added local JPEG, PNG, and WebP re-encoding, quality and width controls, metadata removal, exact size comparison, and download. 2026-10-15：补充结果检查步骤和具体能力边界。