Yep that's a paci (sigh...)
When I picked her up her teachers informed me that while she had done very well for the photo session there was an accident... Yep, somehow she peed on the back of her dress before the pictures were taken. They were able to rinse it out and dry it for the pictures tho. Luckily she had a fresh outfit with her as well. I knew she wouldn't want to be in that outfit all day anyway.