The Edit Custom Sheets option in the scenario editor lets you copy graphics from sheets or paste them into a sheet. However, on Windows, the copied images don't work correctly when pasted into other programs - from memory, I think they paste okay into Paint.Net (possibly missing the alpha channel), but GIMP can't even detect that there's an image in the clipboard.
The Edit Custom Sheets option in the scenario editor lets you copy graphics from sheets or paste them into a sheet. However, on Windows, the copied images don't work correctly when pasted into other programs - from memory, I think they paste okay into Paint.Net (possibly missing the alpha channel), but GIMP can't even detect that there's an image in the clipboard.