I found another variation of this photo of this woman on Twitter by accident, and thought I'd post about her bra and size. In this photo, she's wearing a Curvy Kate Princess bra in pink, which has been available since around late 2009. The biggest band size and cup this bra comes in is a 44K.
It's difficult to tell what bra size she is, but I'll hazard a guess based on some of her photos. In this particular pic, she's wearing the CK Princess, and I can tell a few things from the fit; firstly she is stretching the cups to the limit, so I'm guessing she's wearing the biggest cup size she could get - which is probably a K cup in a reasonably small band size. The centre gore is stretching away from her breastbone by about 2" or more, the straps are straining really badly on her shoulders, and she's spilling over the tops of the cups.
One thing about this bra is that in the smaller band sizes with bigger cups, the back band tends to be very tall/wide where it meets the cups and side panels - so I'm going to hazard a guess that she's wearing a 32K - but there's no way on earth she's a 32K. She seems about 5'4" in height and slim, so given the strain the bra is under, I'm guessing she's possibly a 34L/LL or possibly 32M. (UK sizes).