This is a book on a graphic library, so when they first told me it will be printed in black&white I was quite surprised and puzzled. The editor explained it was to reduce paper copy cost, and that the PDF version will still be in full color, but I would be quite upset if I bought the book and then discover it's black&white without knowing it upfront.
Thus I've asked to at least let the images be downloadable from the book website, so that any reader (either for the paper or electronic copy) can see the pictures as if they're running the programs.
The first request went ignored, but keep pushing got results: now images can be downloaded!! To get them, got the book webpage, then in the "Code Download" section, and request the zip file: in it you'll find either the source code and the images.
The pictures are quite big, because they are the same used for book production (so with specific dimensions and DPI) but you got colors now :)