[DustyPorViva]

You can't :P You have to use something else like Photoshop, Gimp or such.

While paint may get you through the actual work of pixel-art, it's not enough to finalize it. It lacks transparency(just about needed in most situations), you can't index your work(needed for offline viewing in Graal, and to lower file-size), and doesn't do the small stuff like you need here.

I seriously suggest looking into a secondary program to use for your work for final touches. I personally use Paint+Photoshop.