I've managed to make my page work by going back to previous revisions of the post but I would still like to figure out what's happening with this. For this particular post and only this one, if I shift from writing in the HTML format to the Visual side of the editor, my post comes out scrambled in the preview -- looks fine in the Visual side but in the preview page one or all of the photos and captions in the post will have been compressed to a single narrow column, either displayed on top of text or in sequence with text (not embedded in the text as they should be). I can still work with a clean copy of this post in HTML and changes come out fine on the page, but any time I shift to Visual, oops, back to the revision list for a clean copy. Probably I've done something I shouldn't, and it probably has to do with ads and photos, but beyond that I'm lost.
Post is at http://jamestwohats.com/BackPackBlog/?p=1665