Seeing Double

I'm still taking photos and trying to learn something about photography every day even though I'm not posting regularly. I tried this on another day and it didn't work well. I'm not sure I have it down yet. The two figures look to be slightly different sizes. Anyone know why?

My son and family were here today. My almost three-year-old grandson helped me release yesterday's butterfly. Then we watched a "slide show" I had made of a monarch metamorphosis a few years ago. He seemed to enjoy the experience just as much as I did. I'm sure I'll make a nature lover of him.