Why did my phone just take a picture by itself?

My phone was sitting next to me on the arm of my couch, all of a sudden I see my phone light up and an image come up with the shutter sound of a photo being taken. This is very weird and kinda scary. I have an LG Phoenix 3. my own location was the image's location and I went back into my photo gallery and it was there. It's a really blurry image. I can't make it out. Looks like it could be a close up of a tree or something. I was inside and my phone was facing up toward the ceiling. Does anyone of an explanation for this? This has never happened before and so far it has just happened this one time.