What's your take on this picture?

I suspect dust, but I wanted to get some other opinions. Yes, that is my finger that swiped the aperture while open. This was taken about a year ago when I attempted to sell a leather jacket on ebay, and found it while browsing my reject folder. I've gotten similar orb-like anomalies on film in this part of my house. Though, the laundry room being on the other side of this door may lead me to believe that dust is in fact the cause. I tend to steer clear of evidence containing orbs due to their lack of credence, but then again, I'm certainly not an expert in analyzing paranormal photographs.