[Select Inside of Selection?]

Hello all,

 

Let's say I have the black of this image selected.

(source: https://www.seekpng.com/ipng/u2w7u2q8t4y3q8y3_by-chuloc-on-deviantart-cute-anime-line-art/)

 

Now I want to select all the inside areas, without doing Ctrl + Manually select new area.

How do I achieve that?

 

I was thinking about something like a magic wand tool which is not based on color, but is based on whether pixels are selected or not

 

Thanks in advance!