How to I change the default image?

[ashishb]

I mistakenly set it to full how do I change this to medium?
I don't have ~/.config/act/actrc on Mac OS.
I don't even have act directory in my ~/.config

[ashishb]

Found it in ~/Library/Application Support/act/actrc

[celarye]

It is quite annoying to figure this out, the documentation leaves much to be desired. Thank you for coming back and answering yourself.