Is It A Ghost?

A couple of days ago, my dad came home with a puppy, and I took some pictures of it.

I was going through my pictures and I noticed this one picture that had something on it.

I looked closely to see it was, and I have no idea. The puppy seems to know cuz it's looking at it.

Also it doesn't seem to cast a shadow and it's pretty bright behind it, cuz of the flash.

Or it could be something that has gotten onto the lens.

I took this picture with my phone. Google Nexus One.