The speaker starts with a simple confession: they belong in front of an easel. Painting is the one place where their imagination can run wild, and the poem builds that idea by comparing three kinds of settings. In some, even a wild idea like an eight-legged creature with a dinosaur head, a tutu, and bunny slippers would be welcomed. In others, you'd be stared at as if you were the beast yourself. Then there's the easel, where it doesn't matter which setting you're in, because the only judge is you.
The mood is warm, playful, and quietly confident. The humor of the strange creature keeps things light, but underneath is a real wish to be free from other people's opinions. By the end, the speaker imagines the crowds coming to see the finished painting and seeing only their ideas and creativity. The title's pun, "true colors," means both the paint and the speaker's real self, finally on show.