In 2022, AI art went mainstream with tools that convert text prompts into images, where "prompt engineering" is becoming a valuable skill, according to GenerAI CTO Pranav Vaidhyanathan. To compare five tools, the same prompt was used: "A person and a robot standing beside a large oak tree on a hill with clouds in the sky." OpenAI's DALL-E 2, which evolved from a January 2021 model, offers excellent images across styles, is quick, and provides four results at once; it was the only AI model that depicted both the person and the robot. It is a commercial tool offering 50 free credits upon signup, 15 free credits monthly, and additional credits at 115 credits for US $15. Stable Diffusion from Stability AI is also quick and effective, usable free through its demo page, offering results in 30 seconds or less and four variations at once. Its model is open source, allowing serious users to tweak it.