The problem with enlarging photos digitally is that everything gets enlarged, both the good & bad -- because conventional software has no way of defining the objects in a photo, less than perfect edges and details become even more imperfect. Using AI on the other hand, software more or less understands that's a person in your photograph, knows from the vast number of images it's been trained on what a person's supposed to look like, and [hopefully] filters out most of the unwanted noise and imperfections in the original, rather than making that stuff more obvious. How well it works depends on the original photo, the images it's been trained with, and the AI itself -- like facial recognition software, there can be biases.
Adobe, Topaz, & on1 arguably lead the market in AI image processing, and they're expensive -- the Topaz AI enlarger is $100 with 1 year of updates -- making cheaper solutions from companies like Leawo [& DVDFab] attractive. Some people might balk at the prospect of data potentially being available to the Chinese gov, but I'm not planning on enhancing photos from a spy satellite etc. ;) My main concern is that like lots of sites & people Leawo Photo Enlarger uses ImageMagick code libraries, which unfortunately have a long history of security vulnerabilities. stack[.]watch/product/imagemagick/imagemagick/
The registration site [URL in readme.txt] shows your activation code immediately, but appears to record your IP address, showing a site busy notice if you try to get more than one key -- using a VPN works, as long as you're the first one to use that IP address. The actual setup file is just under 1GB -- the regular download is a 3.5MB downloader, that 1st starts an analysis before downloading. That analysis failed in my Win11 22H2 VM, so I downloaded the complete setup file here: leawo[.]org/downloads/photo-enlarger.html
The installed app takes up ~2.34GB, with folders in ProgramData, Pictures, Users\ [UserName]\ AppData\ Local & Roaming. The number of new registry entries isn't bad -- mainly just a Leawo key -- but it does add a phymem2 service which I could not find running in Windows Services app, Task Mgr., or using Process Explorer.