Paranormal lights

We could not see these lights with the naked eye.  They showed up on digital photos taken at night, some with and some without, a flash.  I checked the photos and when the lights appeared, I took more.  I started to take them because it was the anniversary of Damon's death and since orbs had shown up on some photos I took, I hazard a try to see if anything would show up on this special occasion. And mysterious lights showed up.

On the anniversary of the death of my son Damon, July 4th, I took photos in the cottage, some in the dark and some with a flash.  In all instances, lights appeared on the digital prints that could not be seen with the naked eye.  What were they??