The phrase "to do some painting" means to apply colors to a surface, usually using a brush or a roller, in order to create artwork or cover a wall or object with a fresh coat of paint. Full definition
How does your paint sample look next to your tile backsplash? (346living.com)
I really haven't done much art lately, but after that sweet lady did a painting of me it kind of inspired me. (abyersguide.com)
However, the exhibition begs the question: what do her paintings provide that an exhibition of the photographs which inspired the paintings would not? (totalpolitics.com)