Where did the "THUMBNAILS" Come from?
Somehow, iBooks Author inserted a bunch of overlapping oversized images into the very front of my book that show up in the nav tool under "thumbnails".
Where did they come from and how do I delete them? They look like images of Chapter Title graphics, not created by me.
iMac (21.5-inch, Late 2013), OS X Yosemite (10.10.2)