Photoins BG Remover tries to detect the main subject in a photo, select it [basically trace a boundary around its edges], and then delete everything else so you can replace the photo's background. There is a common problem with using AI this way -- it does not always detect all of the subject, &/or it may include parts of the photo that do not belong to the subject, so the software provides tools to manually edit the selection. You basically use a brush to paint the areas you want to add or remove. Using a difficult photo that I use to test apps like Photoins BG Remover, its performance was more or less middle of the road, roughly equal to the Windows Photos app. Both included parts of the photo that they should not have, and more importantly, the quality of the selection edges was rather poor, with a bad case of the jaggies, i.e., diagonal lines look like stair steps. That means that replacing the background will work, but the fact you replaced it will be obvious. The tools to edit the selection were also easier to use in Photos.
The installer is a downloader, with the actual setup file taking up just under 1GB -- the installed app takes up 2.33GB. Folders are added to Program Files, ProgramData, and Users\ [UserName]\ AppData\ Roaming\ & Local\, with an empty folder added to Pictures. I recorded 2 new Leawo keys in the registry, plus one for uninstall. The software itself includes different modules -- they key we get activates one of them, while the rest are available as trials.