Locked Into Page Size

Novels are easy to self publish. There are many companies to choose from.
Books filled with photographs are different. Digital publishing doesn't do well with these. Commercially these are done with offset printing. Private, expensive offset printing leaves the author with boxes of books to store.
My nonfiction books are filled with photographs. Offset printing is not an option for several reasons. I print them on my home printer which produces an acceptable copy.
As my new nonfiction book, "My Ozark Home," nears completion, I started thinking about using a size other than letter size for the book. Commercial books come in several sizes. I went hunting for paper in different sizes.
Special photography paper comes in different sizes. Copier paper comes in two sizes: letter and legal. It comes in various colors, but only two sizes.
As I formatted "My Ozark Home" for 7 x 10 pages, I will now reformat the pages for letter size. This is not a disaster, only a snag.
Now, if only the day lilies would bloom for that last picture. The brush cutter is coming someday in the not too distant future. That would be a disaster.