If we don't want to set the Always-on display's pre-installed themes on the Xiaomi smartphone, we can select our own picture to be displayed there. The selected photo or image will be displayed, and we can set the clock position, text color, and battery status or notification display.

Android 10 (MIUI 12.0)
Step 1:  Open the  Settings
Step 2:  Tap on  Always-on display & Lock screen
Step 3:  Tap on  Style
Step 4:  Tap on  Add from Gallery
Step 5:  Choose a  photo
Step 6:  Set the  text color
Step 7:  Set the  clock position
Step 8:  Enable or disable  Battery / Notifications
Step 9:  Tap on  Apply
  1. Open the Settings
  2. Tap on Always-on display & Lock screen
  3. Tap on Style
  4. Tap on Add from Gallery
  5. Choose a photo
  6. Set the text color
  7. Set the clock position
  8. Enable or disable Battery / Notifications
  9. Tap on Apply

Xiaomi Instructions