This type of orb with a half-moon halo, is often seen in photographs taken into a bright light with mobile phone cameras. These orbs can add to the image or not depending what you want to see.
I took many photographs with my phone camera of this sunset in Darwin harbour (Australia) and all of the images had this same orb in them, which of course varied in position on my screen with the movement of my camera.
The movement of the orb/s in images simultaneously with the movement of your camera, is how you tell if an orb is from lens-flare.