Why this would be helpful

People tend to do their pixel art projects outside of scratch and then import them back in because of poor support. We could make Scratch a quite a bit more useful for pixel art with some small additions to the bitmap editor.

How this addon works

We would add:

1. A colour palette. It should be editable, and reuse scratch's existing colour picker.
2. A much more zoomed in default canvas with the ability to resize the canvas, with the default being 64x64. Canvas has a border and outside the canvas we make it darker, to visually show where the canvas is.
3. Resized checkerboard grid to match the zoomed in canvas
4. Paint brush only allows squares to be drawn, of sizes 1,2,3,4 which you can select via existing brush size.
5. Pixel mode button that triggers features 2-4

This would pair very well with #4067 but that should be a separate addon.

Possible alternatives

Use external pixel art editors, but I view this as a stepping stone to introduce kids to pixel art.

Additional context

piskelapp.com is the ideal ui to base this on: