Why is part of the clock behind a portion of my Lock Screen picture?

First, check to make sure the Low Power Mode is set to "Off" in your settings.

It could also be due to your brightness settings being too low.

A simple restart might help if it's just a software glitch.

Hello~ Did you reposition the picture? Click on below as it sounds like In Depth …

Create a custom iPhone Lock Screen – Apple Support *

*Customize your Lock Screen photo

If you choose a photo for your Lock Screen, you can reposition the photo, change the photo style, and more.

Do any of the following:

• Reposition your photo: To reposition your selected image, pinch open to zoom in on it, drag the image with two fingers to move it, then pinch closed to zoom out.
• Change the photo style: Swipe left or right to try different photo styles with complementary color filters and fonts.
• Create a multilayered effect: If you have a photo that supports layering—like an image with people, pets, or the sky—tap  at the bottom right, then choose Depth Effect.

~Katana-San~