I’ve written about this before… but it’s such an important subject here it is again…
I can’t encourage you enough to contact a knowledgeable professional if you are planning on having one or hundreds of photo/illustration images on the inside of you book. There are so many “if’s” involved and the wrong road could cost not only money but quality in the end product. Be sure that your images are scanned at least 300 dpi, color or grayscale (color can be converted to B&W), jpg, or preferrably tiff and at least 5’x7′ in size. Do not scan already printed images unless that is the only image available and then you might want to invest in a service to do it for you; 72dpi images won’t work unless they begin as a large file in size ie: 22″ so when they are downsized to 5×7 &300dpi the quality will still be there; don’t scan directly into MS Word, the printer needs individual digital files