Farnsworth House Inn ghost

I just returned from a trip to the Farnsworth House in Gettysburg. I spent the night with a friend in one of the haunted rooms. Around 12:30 last night, we were watching TV when we thought we heard someone walking in the attic, which was right above our room. We went up to the attic door and didn't hear anything. I assumed it was just an old house settling. We took a few pictures in the house before going back to our room. The remainder of the night was uneventful and we slept like babies. When I returned home this evening, I was showing my brother some pictures I took. He seemed especially interested in one, and told me to let him zoom in on one section. I didn't see anything at first, but after he pointed it out, it was quite clear. The picture was one I took from the top of the stairs looking down into the entry way of the Farnsworth House. I took this picture when we emerged from the room to search for the source of the "mysterious" foot steps. In front of the door there appears to be an arm with a rolled up white shirt sleeve. I am not sure if you would be interested, but the picture certainly caught my attention and I am an open minded skeptic.