gbabichev/Simple-Layout ? reverse-engineered prompt

Build me a simple Mac app that lets me turn a bunch of images into a clean printable PDF.

I want to be able to add images, pick a grid like 2 by 2 or 3 by 3, and have the app place everything onto pages for me with a live preview. It should support common paper sizes like Letter, Legal, A4, and Tabloid, let me switch orientation, and also let me set a custom page size if needed. I’d like headers, notes, margins, padding, and basic image cropping options like fit or fill. It should also let me move pages around, add blank pages, reuse the same image more than once, and save the whole layout so I can come back to it later.

Please make it feel simple and focused, with no account or cloud stuff, and keep everything local on the Mac. I should be able to preview, export to PDF, and print straight from the app.