Normally, only Masterpieces can be sold there.
Taking the Painting Career lets you sell all kinds of Paintings to the Art Gallery, which buys your paintings for 20% more than their face value.
You can now get promotions with careers.promote painter - you can also see all Career Cheats or visit a full list of Cheats in The Sims 4. Press Control + Shift + C then type testingcheats on and press enter.
