I's been trying to get in touch with the DoE over their website for loan payments that won't let me register--it says I already have an account, which I don't and never have. I finally got to talk to a human. And then the human hung up on me.
What I like about Photoshop is that the crop tool works by proportion rather than the literal dimensions. So, you can crop from a huge image and still end up with a 80 x 165 end product, automatically resized.
Whereas in Paint, you have to resize until you find the approximate size and then manually crop.
I'm fairly certain GIMP will have a similar tool to the one in Photoshop.
I suspect the source images are not very high quality.
Half of avatar making, in my opinion, is high quality images. The other half is choosing the best part to crop. And I think you've got a grasp of that, except the first one has way too much space between Boba's head and the top of the image--but that's probably because of the source image as well.