There's now a color selector, space to select the color. Click to draw, s to save, l to load, f to see featured art, and i to import an image which rather than replacing the old image will just put the new image layered above the old one. Paint 2.0 codes work for paint 3.0. And now with this project https://scratch.mit.edu/projects/608724578/ you can turn Paint 1.0 art into Paint 2.0 art which works for Paint 3.0.
I recently came back and fixed that color selector, although I'll need to brighten the image, originally I had it darker than necessary so that I'd have it be regular brightness when you increased it, in retrospect I should have just used the ghost effect instead of the brightness effect due to the black background, I've now changed it to this but the image is still adjusted weirdly.