[Bug Report] 导出图片时，导出的文件扩展名为PNG但内容是JPEG

[yanhuixie]

Prerequisites

• There isn't an existing issue that reports the same bug to avoid duplicates.

• The provided information offers a minimal reproducible example of the bug, (Why create a Minimal).

• For Q&A, please open a GitHub Discussion instead.

Version

0.10.3

Reproduction Link

No response

Describe the Bug

const imgData = canvas.toDataURL('image/jpeg');

aLink.download = ${fileName}.png;

请参考这两行代码，exportScreenShot时指定了jpeg格式，fileDownload 时写死了png扩展名，所以导致了不一致。
目前fileDownload 只有这一处地方使用，但是从函数的设计意图来看，似乎是通用的，所以扩展名可能需要根据条件来枚举？

System Information

Contributing

None