No it isn't a URL. But that would indeed be the way they could make it work. If they did that, then...
If you don't have the app installed it installs it from the web site. If you have it installed then the app takes over instead of the web browser. That is how many apps work (eg Reddit).
If the CPU power was there then a browser plug-in would allow you to do it by right clicking on any image to instantly generate a cum-shot or worse: a gun-shot.
It could also generate some beautiful things like showing the person ageing backwards into a baby. Actually my friend tried that but it just showed him holding a baby (he used FramePack and ran out of credits before succeeding).
My point is that this raises philosophical thought police issues.
No it isn't a URL. But that would indeed be the way they could make it work. If they did that, then...
If you don't have the app installed it installs it from the web site. If you have it installed then the app takes over instead of the web browser. That is how many apps work (eg Reddit).