So I was making a "First Halloween" picture book for my son, who is 11 months old tomorrow, on www.shutterfly.com and was going to an 8x8 book but when i was placing the photos there seemed to be very little detail in the photos and fairly grainy. Really they looked like just plain crap. I have an A33 as most of you know and shoot in RAW, The photo size is 4592 x 3056.

So my question is How big can i make these photos if i wanted to get prints made with out loosing any quality??