[Feature] Modify the DPI of the exported image

[HoeYeungHo]

• Searched existing issues to avoid creating duplicates.
• Searched http://support.typora.io/ since it may be already implemented.

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I hope that when using Typora to export an image, I can not only adjust the width of the image, but also adjust the DPI of the image.

DPI of the image export from Typora just 72. When I set the width of the image is 1080, I find the image is too vague!

I'm not sure whether DPI of the output image can be adjusted by modifying the configuration file, but I think it would be better if it could be set in Typora

Desktop (please complete the following information):

OS: Windows 11 64bit

Typora Version
1.4.8.

[abnerlee]

The image is captured from the screen, so the highest DPI will be your screen dpi.