Download FFPx right now; this is a full working version with the limitation of a maximum of 10 images. If you decide to buy the full version, you'll receive a software key that removes the restriction.

FFPx runs under Windows 7, 8, 8.1 or 10 using the .NET 4.61 environment. .NET 4.61 is built in to Windows 10 but may need to be downloaded for earlier versions of Windows - the installer handles all of that for you.