Thanks Paul. I will test your suggestions.

What I don't like about the screenshots is the greyscale darkness. It just makes the book (other books I have seen) depressive.

Alternative is individually make the B&W screenshots brighter if possible at all. It is time intensive, but that maybe only way. I may have 500 screenshots by the time I am finished.

While I like screenshots is to convey a sense of reality to the reader: this is what you are going to see when you become a database designer, an SQL programmer.