Dear departed
I never seem to make things easy, using the liquid-rescale plugin is certainly a hard way. It is because I have been using Gimp for a long time.
This using standard Gimp.
For your image test2.xcf
(1) You can remove any anti-aliasing with a very big value (0.99) in Layer -> Transparency -> Theshhold Alpha
(2) Apply Image -> Zealous Crop which removes unused space.
30 second example: https://i.imgur.com/QXkAgvR.mp4
I never seem to make things easy, using the liquid-rescale plugin is certainly a hard way. It is because I have been using Gimp for a long time.
This using standard Gimp.
For your image test2.xcf
(1) You can remove any anti-aliasing with a very big value (0.99) in Layer -> Transparency -> Theshhold Alpha
(2) Apply Image -> Zealous Crop which removes unused space.
30 second example: https://i.imgur.com/QXkAgvR.mp4