1. **Open Settings**: Tap on the "Settings" app on your iPhone's home screen.
2. **Go to Wallpaper settings**: Scroll down and tap on "Wallpaper."
3. **Choose a new wallpaper**: Tap on "Choose a New Wallpaper." You'll have several options:
- **Dynamic**: Animated wallpapers that move with your device's motion.
- **Stills**: Static images that don't move.
- **Live**: Live photos that animate when you press and hold on the screen (available on certain iPhone models).
- **Photo Library**: Choose a photo from your device's photo library.
- **Solid Colors**: Choose a solid color background.
4. **Select the wallpaper**: Browse through the available options and tap on the one you want to use.
5. **Set the wallpaper**: Once you've selected the wallpaper, you'll have the option to set it as your Lock Screen, Home Screen, or both. Choose the desired option, and then tap on "Set."
6. **Adjust the wallpaper**: If necessary, you can pinch and zoom to adjust the wallpaper's position and size. When you're satisfied with the placement, tap on "Set Lock Screen" or "Set Home Screen" to confirm your selection.
That's it! Your iPhone's wallpaper (screen picture) is now changed to the new image you selected. You can repeat these steps to change the wallpaper as often as you like.