I have been doing some testing over the last few days of Topaz AI Gigapixel, this is a piece of software that has one sole function; to enlarge images. Whilst that is oversimplified it uses machine learning and AI to work out how to best enlarge your image (potentially up to 600%) whilst retaining the features and detail within the image and trying not to introduce any artifacts as a result of the enlargement process. Now I (think i) know what you are thinking, Photoshop, Affinity Photo, and many other programs can enlarge images which is true but generally, they don't always preserve the detail in the image which is where this program comes in.
My first impression of using the software is fairly good, it should be noted that this is not fast software by any stretch of the imagination. The best work-case is usually to prepare your image as much as you can (e.g. Cropping) and then feed it through the software in a batch overnight (if you have multiple images). Ideally, the software uses a supported GPU to accelerate the computation that is required to determine how to best enlarge the image (using AI) which is the fastest mode, but if not there is also a supported CPU mode (which is slower) but more useful if your GPU is not supported.
In my test below, I took three images and enlarged them using AI Gigapixel (they are slightly cropped into the feature of interest), within the gallery you will see [original] signifying the starting image or [enlarged] signifying the enlarged image from Topaz AI Gigapixel. I will let you make your mind up on the detail.
If you are interested in this software, I have provided a link below (affiliate link):
NB: I was not paid to conduct this write-up, and purchased AI Gigapixel myself. If you do purchase from the link above then I may receive a small commission from Topaz however, that does not change my opinion of the software, nor my write-up.