Well, the photographs in books are generally copyrighted along with the content of the book. So you should not be taking those pictures. Although, it's quite possible that nobody flags your hub if the pics are not watermarked prominently, and it might not be unpublished - but it's violation of copyright none the less. Publishing any copyrighted picture anywhere without permission is equivalent to stealing.
On the other hand, if you can find pictures in a book which are shared under create commons license (you can use them for free, but you should credit the creator), you should be able to use them. Study the license carefully in this case - there are many versions of creative commons license.