Hire a vetted muralist, street artist, or graffiti artist.

A muralist is trained in composition, color theory, and surface preparation. Their work skews illustrative, figurative, or decorative — the right fit when the brief is 'we want a beautiful, considered image on this wall.'

A street artist works at the intersection of fine art and street culture — stencils, paste-ups, stylized characters, pop-art commentary, large-scale figurative work. The discipline that gave us Banksy, Shepard Fairey, and Faile.

A graffiti artist works in the lettering and aerosol tradition — tags, throw-ups, wildstyle, characters. The craft is the letterform and the can control. It's the discipline that started the whole street-art conversation and still anchors it.