Change size in different units

[JohnDumpling]

Is your feature request related to a problem? Please describe.
I recently wanted to resize a picture to a specific size in centimetres. This was not possible with your app, thus I opted for a simple online tool.

Describe the solution you'd like
It would be great if your app supported resizing by centimetres or inches besides pixels. This could be enhanced further by adding the ability to change DPI from the default value (something like 3 pre-set options - 50, 150, 300 DPI - feel free to change the values)

Additional context
For inspiration, I attach a link to the online tool I used here