From left to right:

1. Original 32x32px density
2. Updated 64x64px density, no borders
3. Used LayerBorder script to add 1px black border around each layer
4. Used ImageBorder script to add 1px black border around the whole image

I continued converting my main character to 64x64, but at the same time I wanted the black border around the player to be a bit thicker. I also wanted to add a 1px border between the different layers. I already had a script to outline the whole image for Aseprite, so I created another one specifically to add a 1px border around each layer as well. The Aseprite scripts are open source and free to grab from the link below if you want them

https://github.com/alexpennells/AsepriteScripts