IF THIS (You are tagged in a FB photo), THEN THAT (set it as Android wallpaper)
Trigger service: Facebook You are tagged in a photo: This Trigger fires every time you are tagged you in a new photo. NOTE: Facebook privacy settings may block IFTTT’s access to some photos you are tagged in. Action service: Android Photos Update device wallpaper: This Action will update the wallpaper on your Android device from the image URL you specify. If G.R is tagged in a photo, then update device wallpaper.