A few days ago I was taking a series of photos of flowers from my garden. Two last were taken when it was dark already (i.e. with a flash). Yesterday while I was saving all photos on my computer, surprisingly I found out there is "something" else on one of them (the other taken a few second after doesn’t show anything like this). No clue what this might be - while taking photos I didn't hear anything as well as I did see nothing except flowers obviously. No other person was with me there....