Custom Image Editor

I've noticed that in Construct 2's preferences, there is a parameters that allows you to change the image editor:

As I couldn't find anyone talking about it, I ask if and how I can add/make my own image editor.

The main reasons I would want to add/make a new image editor is to add things that aren't in C2's image editor (Circle for exemple) and to try and make the same thing that GMS:2 does with it's image editor, aka drawing while having the animation playing.

Ashley if you could tell me if the feature is working and has just been ignored, or if it has been discontinued, that'd be cool.

It means open the image in photoshop or gimp or something like that.

Yes, I know. What I asked was if there was a way to make a custom image editor that would return animations, frames, its parameters and so on like the default one does.

Sorry, the external tool is only for editing a single image.

Ashley Ok thanks for answering