Although this is very similar it isnt it.
The one I used even had some of these wallpapers but a really easy UI and you could add your own wallpapers all through gui without terminal.
Starting to think i dreamed it but my wife insists I didnt shut up about it when I had it the first time.
Something you need to consider even before all this, is what other people will do with the photos once they have them.
I’ve been through a similar situation recently and had to lay out ground rules for what people were allowed to do with the photos and where they could be saved. I made the condition that if they wanted to see photos I would only send them through signal. Past that point you just need to trust that grandma who downloads the image to her iphone doesnt have iCloud enabled by default and boom your childs image is now in the hands of apple. (Or any other auto backup cloud host)
Be prepared for some outright childish behaviour from people you thought were adults when you tell them they cant take their own photos unless they show you they dont have auto sync to iCloud enabled…
The only way to truly keep your kids image out of the cloud is to never let anyone else have possession of it to begin with unfortunately.