Proof Card Generator - Software or Photoshop Script

I require a some simple software to work on Mac OS 10.15.2 (Catalina )to generate proof cards for my school photography business. I will need to start with a jpeg image (the background of the proof card) and then the software should lay over the background jpeg a series of other jpegs and their file names is a set place. (See attachment). The software should allow me to set how many images I want to be overlaid on the background jpeg. For example: I have a folder containing 120 images (4 photos each of 30 children) Image 1,2,3 and 4 is child one, numbers 5,6,7 and 8 are child two and so on. - The software when finished will produce 30 proof cards each containing 4 images of each child. I need the ability to change the layout though so that if I only have 3 images of each child I can have it lay them out in 3's etc. I have previously had something like this already working on Mojave - but since the upgrade this has stopped working - so if you could simply fix what I already have that could also be an option (the previous software was written in python) - PLEASE ONLY BID FOR THE JOB IF YOU UNDERSTAND THAT I AM A PHOTOGRAPHER NOT A PROGRAMMER - I NEED SOMETHING BASIC AND SIMPLE. Thank you