Using the Blurb software that you download onto your computer, you follow the steps to "slurp" your blog posts into the software, and from there you tweak each page to look how you want it to look. It lets you know if the picture isn't good enough quality for the size you chose, and so you make it smaller. It moves text to another page if it has gone over the formatting for that page. It's pretty easy to work with.
Once you have your book how you want it, blurb uploads all your work, and within a week, you have a hardbound copy of your blog in your eager little hands. I think that's pretty cool. My book is 8 1/2 x 11 size, it has 388 pages and is hardback. Some of my blog posts took up a few pages, and some were short enough that I could squeeze a few posts on the same page. All in all, I love my blog book. I encourage any of you who have blogs, to get it in print. It was economical, and the print quality is good. Basically, if your picture is good quality, it will print in good quality.