The thing i love about Hamo is that how he is always able to get in the way no matter what happens. I can almost see Hamo Smirk while the picture was taken.
I'd say that she feels uncomfortable because every picture of Len in the cell phone has some other thing in it, like Rin's head in 3rd panel, and Hamo in the 4th. As we all know, Neru is a big Len-fan, she probably just want a nice taken picture of Len...