What is the free AI that enhance photos?

Excuse me, could you please elaborate on the concept of a free AI tool that enhances photos? Are you referring to a software or application that utilizes artificial intelligence algorithms to automatically improve the quality of photographs? If so, could you provide some examples of such tools and their specific features that make them effective in enhancing images? Additionally, are there any limitations or considerations one should be aware of when using these AI-powered photo enhancement tools?