Not an endorsement nor a negative, but just a couple of data points from me:
I worked with an internet group a long while back to prepare and produce a book of our collective works for sale to raise proceeds to help tsunami victims. It was called "Images to Brighten Our World". It was full of great, upbeat images, and we hoped it would raise a lot of cash.
1. It was more difficult to create than we expected; there are a lot of details in putting a book together - even a picture book.
2. The self-publishing cost was higher than we expected, even though we got the printer to give us a "charity" rate (meaning it was at their cost, no profit).
3. A few hundred copies were all that were sold - directly off the Lulu.com site and mostly to those of us who had photos in the book.
I currently have a book of astroimagery about to hit the shelves through a commercial publisher. Some details:
1. Again, much harder to prepare and polish than you would think. Literally MONTHS of work beyond what I thought it would take.
2. It's a niche book, and timely (e.g., international year of astronomy).
3. I will be getting only a tiny fraction of the sell price. The publisher/printer gets some, but the distributors take a lion's share of the profits.