This is "Ballet Dancers" by Hilaire-Germain-Edgar Degas, painted in 1888. The vibrant colors and informal portrayal of four ballerinas in the wings reflect the influence of Japanese prints on Degas' work. Note how the dancers are placed along a diagonal line within an asymmetrical composition cropped at the lower right.
In this piece, we see the physical demands of ballet dancing through the relaxed poses of the performers. The first young woman squats down, maybe to tend to a sore muscle or adjust a ribbon, while the dancer behind her rests her head in one hand. A third dancer holds a brightly colored fan, and a fourth leans against a wall.
The pastel technique favored by Degas creates vivid colors, but what's fascinating is that this seems like an improvised piece without preparatory drawing. Yet, each figure here was derived from earlier studies of individual dancers used as source material for multiple finished pieces.
Ballet Dancers hangs in The National Gallery on Trafalgar Square, London — free to enter. Point your phone at any artwork there and audioguide.london plays a free audio guide in six languages — no app download needed.