Everything I've heard in storm spotter class is that the funnel has to touch the ground to be considered a "tornado". And that doesn't mean you'll see the vapor vortex touch the ground, the vortex may be there and not be visible. Usually the sign that the vortex has touched the ground is the presence of debris, and I can't see that in that particular photo. Doesn't mean it didn't happen 30 seconds before or after the photo, I just can't see it in that particular photo.
I was driving back into Dallas up I45 and the sky looked pretty freaky, but I never saw anything. By the time I pulled out my HT - they were spotting a rotating wall cloud over Mesquite that never materialized into anything. I was kicking myself because I've got a brand new VHF radio and antenna at home, still in the box, that I've been meaning to mount in the truck specifically for this kind of thing.