iPhoto has not really been supported since 10.10.3.
As for PrintShop, you'll want to get a registered copy of the software to be able to show the slideshows created with it.
https://www.mackiev.com/printshop4/ is available for 10.13 and 10.14. 10.15 and later aren't listed as supported, so don't upgrade to 10.15 or later until you can find a counterpart.
You may want to see if Printshop can save your slideshow to Quicktime, or Open Quicktime Player to record a screen video before bringing it over to 10.15 or later.