> What I’m asking is how do you make a wallet pass from a static image. Is is difficult? Is it simple? What are the steps?

It's simple, there are lots of libraries that can generate it. You can probably even ask Claude Code or something like that to generate you one.

I understood your question as: can I do this myself or do I need an app and the answer is that you can do it yourself. The documentation for it is easily Googleable.

What you need is a signing key so you will need to pay the apple tax.