I got a bit confused when I watched issuu´s video in my last post because I had assumed that anything you want to upload has to be in pdf format. Maybe I was wrong all the time or it is new that you can also upload word-files and power point-files. I just tried it out and yes, it works.
Still, for photo books I would use photoshop, then save as pdf, then merge and then upload as book, as described in my last article. I need to add that if you want a picture stretching over two pages, which can be nice for landscape formats you need to create a double page background ( instead of 15x15 double the width 30x15), position your photo accordingly on it and then cut up into two pages. Take care then that these two pages appear together, so after the cover counting as page1 they should be pages 2 and 3, or 10 and 11...)
I also wrote that anyone can embed your work for their purposes - you can avoid that in choosing under publishing options: privat - only you can access it then and embed it. The disadvantage is that Issuu will not list it then and honest, a big number of viewer traffic from all over the world is generated by browsing issuu viewers. By the way you can access all your data on that by going to My library after signing in, click on any of your publication, then click statistics.