Feature request: Allow uploading/saving of Brush Icon images

Right now, the editor looks like this:
It’s kind of strange to have this incredibly limited canvas-within-a-canvas for drawing/editing a new brush’s image, especially when we’re already using this drawing software to… you know, draw images.

Suggestion 1.) Add the option to upload a brush image. Maybe add a dialogue window that informs the user that if the image isn’t square (ie: 256x256px) the icon might not look correct, and ask them if they want to proceed with uploading as a brush icon. Maybe even replace the “edit” option altogether.
Example of possible usage: porting a Krita brush’s settings/style to MyPaint, and using the brush image from Krita without needing to draw/create a brand new brush image.

Crude Example:

Suggestion 2.) Create the option of saving a MyPaint file as a brush icon image, with the recommended format (such as .png or .ora or something) Since MyPaint has improved so much as a software, and we can manually set the image size, better utilize paint layers, and such, it’s possible to directly draw and edit the brush icon in MyPaint itself.
It could default to saving as a .png (or whatever format) with a solid background. And this again, is an opportunity to prompt the user if their document frame isn’t square, and if they want to proceed with saving, or edit the document frame to be square first. Maybe by saving it this way, MyPaint can show the user their saved brush icon, so they can readily access it and use it as a custom brush image.

Crude example:

A quality of life feature suggestion, just because I feel like the process for changing a custom brush’s icon is kind of unintuitive.

MyPaint version: 1.2.0 stable
Operating system: Windows 10, 64-bit
Hardware: Acer Aspire + Yiynova MVP10U screen tablet, MS Surface 3 (non-pro)

Wouldn’t the better way to handle is to just open that icon on the canvas with the frame limited?

And where exactly do you open the brush icons of the brushes you download, or the images of the brushes that come with the software?

Update: found the answer- it’s in App Data → Local → Mypaint. Which is hidden, and/or not accessible to every user possibly because of user permissions.

Again, the question I’m posing here is to make the process more intuitive for users. Not to have to go through a long and complicated process to begin with to do a simple task.

Do you know how hard it would be to launch a whole new instance of MyPaint when you click “edit icon”, maybe with the frame limiter enabled already? That might be a good compromise.

Although, this doesn’t address the other issue-- that editing a brush icon that is 256x256 pixels is almost a task for a pixel-artist. For a lot of brushes you really need to work at much larger size and then scale back down to 256x256. OR…

We just allow really large brush icons and scale them down in the GUI. That might also help with high dpi. HD brush icons would be spiffy… . .