Step one is definitely to select your design software. They all work about the same, with the proviso that the more you pay for it, generally the more easily it does things. (Like anything in life.)
But there is a learning curve associated with whichever one you get. (I use Illustrator, which is excellent but pricey, but Inkscape can be made to do everything as well, and it’s free. There are a few experts on both programs here to help with questions. For some of the other options there is less help available.)
It’s easy to create a photo ornament in either program…here are a couple of writeups on how to do it in Inkscape and Illustrator.
