It would be wonderful if Paint.net had smoothing feature in Magic wand tool.
You can do powerful things with tolerance/smoothing parameters (I had abuse it lot, long ago in Paint shop pro ).
This feature would be great as standard part of Paint.net.
I have lot of images which I have to crop and resize to same size.
Selection => Fixed Ratio => Saved Preset (eg. 700x300) => Crop&Resize (which would crop and downscale or upscale image to targeted size).