The startup, funded by Microsoft Corp., said in a blog post that its latest technology is "multimodal," meaning images as well as text prompts can spur it to generate content. The text-input features will first be available to ChatGPT Plus subscribers and to software developers, with a waitlist, while the image-input ability remains a preview of its research.

The highly anticipated launch signals how office workers may turn to ever-improving AI for still-more tasks, as well as how technology companies are locked in competition to win business from such advances. Alphabet Inc.'s Google on Tuesday announced a "magic wand" for its collaboration software that can draft virtually any document, days before Microsoft is expected to showcase AI for its competing Word processor that's likely powered by OpenAI.

The startup's latest technology in some cases represented a vast improvement on its prior version known as GPT-3.5, it said. In a simulation of the bar exam required of U.S. law-school graduates before professional practice, the new model scored around the top 10% of test takers, versus the older model ranking around the bottom 10%, OpenAI said.

While the two versions can appear similar in casual conversation, "the difference comes out when the complexity of the task reaches a sufficient threshold," OpenAI said, noting "GPT-4 is more reliable, creative, and able to handle much more nuanced instructions."