Photo Widget keeps showing a deleted photo

If your photo widget on your iPhone keeps showing a deleted photo, here are some steps you can try to fix the issue:

1. Remove the widget and re-add it.
2. Restart your iPhone.
3. Sometimes, deleted photos can still show up in widgets if they are in a hidden album. To check if this is the case, go to the Photos app, select "Albums," and see if there are any hidden albums. If there are, check if the deleted photo is in one of them and delete it from there.
4. Probably you have synced these Photos from your Mac/PC through iTunes. UN-sync then they would be gone from iPhone. UN-Sync photos to your device
   1. Connect your device to your Mac.
   2. You can connect your device using a USB or USB-C cable or using a Wi-Fi connection. To turn on Wi-Fi syncing, see Sync content between your Mac and iPhone or iPad over Wi-Fi.
   3. In the Finder  on your Mac, select the device in the Finder sidebar.
   4. 
   5. Select Photos in the button bar.
   6. 
   7. Note: When iCloud Photos is turned on, no photo syncing options appear when you select Photos in the button bar.
   8. Select “Sync Photos to your device from” tickbox, then choose Photos, Pictures or a folder from the pop-up menu.
   9. 
   10. Uncheck Sync photos
   11. Click on Apply / Sync

If none of these solutions work, you can try resetting your iPhone to its factory settings.