^ Well, the one thing you have to remember about the photo books though is that they always choose shots/angles and bikinis that make the HP girls often look bigger than they actually are. Not to mention editing afterwords. Even so, her breasts look bigger now than in any of those photos.
If you look at the full photos in the photobooks that those pictures are from, her breasts look small to medium compared to the rest of her body.
For Maki I remember (as did pretty much everyone else at the time) that her chest looked noticeably quite a bit bigger after supposedly being "sick." When you compare video of her prior to 06 (HP elder club winter '06 being the last concert with her normal chest) to anything after that, you definitely see a difference.