图片格式转换Image Converter
图片格式互相转换(JPG/PNG/WebP/BMP)Convert image formats (JPG/PNG/WebP/BMP).
关于 图片格式转换About Image Converter
不同场景需要不同图片格式：网页推荐 WebP、照片分享常用 JPG、图标与透明素材需要 PNG。本工具支持 JPG、PNG、WebP、BMP 等常见格式互相转换，浏览器本地完成，无需安装软件。Different scenarios call for different formats: the web prefers WebP, photo sharing uses JPG, and icons or transparent assets need PNG. This tool converts between JPG, PNG, WebP, BMP and more, right in your browser with nothing to install.
使用方法How to Use
- 上传需要转换的源图片。Upload the source image.
- 选择目标格式。Choose the target format.
- 对有损格式可调整输出质量。Adjust output quality for lossy formats if needed.
- 点击转换并下载结果文件。Click convert and download the result.
常见问题FAQ
转成 JPG 后透明背景没了？Why did transparency disappear after converting to JPG?
JPG 不支持透明通道，透明区域会被填充为纯色（通常为白或黑）。需要保留透明请使用 PNG 或 WebP。JPG has no alpha channel; transparent areas are filled with a solid colour (usually white or black). Use PNG or WebP to keep transparency.
反复转换格式会损失画质吗？Does repeated conversion degrade quality?
每次转成有损格式都会引入一次损失。建议保留一份无损原图（PNG），需要时再从原图转换。Each lossy conversion adds one generation of loss. Keep a lossless master (PNG) and convert from it when needed.
BMP 转 WebP 能小多少？How much smaller is WebP than BMP?
BMP 是不压缩的位图格式，体积通常是同画质 WebP 的十几倍甚至更多，转换后瘦身效果非常显著。BMP is uncompressed; it is often ten times larger or more than an equivalent-quality WebP, so the savings are dramatic.
相关阅读Related Reading
图片加水印的正确姿势：可见水印、盲水印与版权保护的边界Watermarking Images the Right Way: Visible Watermarks, Blind Watermarks and the Limits of Copyright Protection
水印不是防盗的银弹，但用对了能显著提高盗用成本。本文从可见水印的摆放策略讲起，对比盲水印与数字指纹的原理，并给出版权保护的真实边界与实操建议A watermark is no silver bullet against theft, but done right it raises the cost of misuse considerably. This article starts with visible-watermark placement, compares how blind watermarks and digital fingerprints work, and lays out the real limits of copyright protection plus practical advice.
网页图片格式怎么选：JPG、PNG、WebP 使用与压缩实践Choosing Web Image Formats: JPG, PNG, WebP and Compression in Practice
图片通常占网页体积的一半以上。本文对比三大格式的特点与适用场景，给出选型决策路径与压缩参数建议，帮你把页面加载速度提一个档次。Images typically account for over half of a page’s weight. This article compares the three major formats, offers a decision path and compression settings, and helps you move your page load time up a class.
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