PNG to JPG: When and How to Convert
Understand the real difference between PNG and JPG, what happens to transparency, and convert the right way for your use case.
搞懂 PNG 与 JPG 的真正区别、透明通道会怎样，并针对你的场景用正确的方式转换。
一句话区分 PNG 与 JPG
PNG 是无损且保留透明；JPG 是有损且体积小得多，但不支持透明。光这一点几乎决定了所有场景。
透明区域会怎样？
JPG 无法存储透明，所以转换时透明像素会被填成白色。对截图、插画或白底 Logo 来说，通常正是你想要的。
什么时候该转
- 用 JPG：照片、大图导出，以及一切「体积重要、透明不重要」的场景。
- 用 PNG：需要透明底、清晰边缘，或想无损归档时。
在这里怎么转
打开「PNG 转 JPG」一步去掉 alpha 通道。如果源文件不是 PNG，「图片转 JPG」支持任意浏览器可读格式。想反向且保住清晰边缘？用「图片转 PNG」。
一个坑
JPG → PNG 不会凭空找回丢失的细节，只是把现有像素重新打包。尽量用你手里最高质量的原图转一次到位。
Understand the real difference between PNG and JPG, what happens to transparency, and convert the right way for your use case.
PNG vs JPG, in one line
PNG is lossless and keeps transparency; JPG is lossy and much smaller, but has no transparency. That single difference decides almost every case.
What happens to transparent areas?
JPG cannot store transparency, so transparent pixels are filled with white when you convert. For screenshots, illustrations, or logos on white, that is usually exactly what you want.
Convert when you should
- Use JPG for photos, large exports, and anything where file size matters and transparency does not.
- Use PNG when you need a transparent background, crisp edges, or lossless archiving.
How to convert here
Open PNG to JPG to drop the alpha channel in one step. If your source is not PNG, Image to JPG handles any browser-supported format. Need to go the other way and keep edges sharp? Use Image to PNG.
Gotcha
Converting JPG → PNG does not magically recover lost detail; it just repackages the existing pixels. Convert once, at the highest quality you have.