Why white is the whole composition
A pure white dog is a portrait painter's hardest subject and most satisfying when it works. The Maltese gives the painter only two anchors — the dark eyes and the black nose — and lets the silken coat carry everything else as texture and light. Watercolor handles this beautifully, the coat dissolving softly at the edges while the dark anchors hold the face.
Where the refinement lands
Art Nouveau was practically written for a small white silk-coated dog — the long flowing line of the medium matches the long flowing coat. Duchess holds the breed's gentle aristocratic bearing without overplaying it. Cherry Blossoms gives the white coat a faint pink wash that flatters the breed's delicate features. Watercolor remains the safest classical choice.
Coat length tunes the portrait
Show-coated Maltese (with the floor-length coat) read most clearly in Art Nouveau and Duchess — the long line is the portrait. Pet-clipped Maltese (with a shorter puppy cut) read as cleaner geometry and suit Watercolor and Cherry Blossoms well. We read the coat length from your photo and tunes the styling accordingly. Either is breed-correct.