Crop function in Viewer

[TVETVE]

What would you want to be added to satdump?
A clear and concise description of what the idea/problem is.
I would like to crop the picture in Viewer before saving it. That would remove the need for opening the picture in another program.
Describe the feature you'd like to have
A clear and concise description of what you want to happen.

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Here you can for provide more information about what you'd like to see as the end result. Feel free to also post images if you have ideas regarding the UI