There's an image folder, where you can put all your images. You will need a "cover.gif". It is already in "images". Use this (as a "template image") to create your own cover image and don't change the name. Then put all other images, that are being used in your book, i.e. in the xhtml of your book, into this folder ("images"). For your images chose any name, but keep them png image files or convert them to png files. Very important: The image files or the xhtml files should not start with digits. Don't use jpeg. Remove every image from this folder that is not utilized. The opf generator uses png by default. The only other file type used is the file "cover.gif". Then create your (xhtml) content in this order. Don't do it like I did it. (See the black arrow?) To keep the files in order, the file after x009.xhtml should be x0091.xhtml and so on. Leave x000.xhtm, x001.xhtml both in the folder and start with x002.xhtml, rest is up to you. x000.xhtml is used for the titlepage by default, x001.xhtml for the preface and x002.xhtml for the first page of your book. You can change the content of these files, of course.