Some Cool Pics Taken At Lusk's Lock

I took over 50 pictures at Lusks Lock the other day.  Out of all of them, these two have a strange anomaly in them.  I was taking a picture of the creek and in the center it is like something nearly invisible is standing there, in between the view and me.  In the second picture, a similar anomaly is hovering over Will and Briana, only smaller. Click on the pictures to make them larger to see better.  I checked my camera lens and it is clean.  These are the only two pictures that have this on them.