how do I put a photo on the lock screen?

Hello patfromtinton Falls,

Steps do vary depending on your iPhone version. If you have the new iOS 16 version, then see Change the wallpaper on your iPhone - Apple Support

1. In the Settings app, tap Wallpaper.
2. Tap Add New Wallpaper.
3. Tap Photos, People, or Photo Shuffle to choose your own photo. You can also select a wallpaper from a category like Weather & Astronomy, Emoji, Collections, or Color.
4. If you want, you can customize your wallpaper further. Then tap Add.

Thanks for using Apple Support Communities!