TikTok is rolling out a set of new artificial intelligence-powered advertising features, including the ability for marketers to use text or still images to create AI-generated video for the service. Marketers can upload an image of a product they want to feature, or write a short text prompt describing the kind of video ad that they want, and TikTok’s AI tools will produce various five-second clips that can then be used in an ad, the company announced Monday....