I am relatively new to PSE 10 and I want to create a Photo Collage. So, I selected 8 or more photos to be a part of my collage and when I click ok to have the photos added, I only see maybe four photos in my layout. The rest of the images are blank that say something to effect 'to add more photos click here or drag and drop photos'. Why are these spaces left blank? Where are the other photos that I originally selected to be a part of my collage?