You could probably do something like this quite easily in Inkscape. You can download it for free at inkscape.org

It's a vector program, which will allow you to scale your images to any size you need without loss of quality. You'd create the images in Inkscape then export in PNG or probably PDF for a printer. As with all new software, there's a bit of a learning curve, though once you the hang of the basics, it's quite straightforward for simple stuff. I suggest watching some 'beginner guide' tutorials on Youtube to get an idea of the basic tools. I like this guy's tutorials. He's got some beginner/intro tutorials as well as more advanced stuff.

If you want something a bit more artistic, Gimp (free) or Photoshop (not free) are packages to consider. There's also Affinity Photo and Designer, which are modestly priced and might do what you need.