Decide on the word or image you would like to fold. Open your graphics program. I used Paint.net
which is a free graphics program. Most photo editing software should work, but the specific instructions for scaling the image may be different.
Set canvas height to the height of the book and set the width wide enough to fit the word or image. Insert the image or select the font you would like. For this project I used the word Love in Coopers Black font. This font has thick letters that will show up well. Type word in a size appropriate to the height and center word or image. Set the contrast to 100 (under Adjustments tab) to ensure solid color with no gray edges.