Not knowing what your icons look like its not easy to tell you. I would, if they are valuable hand painted or framed, put them in your carry-on.
From firsthand experience I know that baggage handlers stack your check-in luggage in the corners of huge warehouses by competing with each other to see how far and how near the top of the pile they can throw the luggage. So no valuable or fragile items should ever be in your check-in luggage, in my opinion.
You can protect the corners of framed pictures from accidental knocks, if you are fussy, with small folded bits of cardboard taped on to each corner. Unframed, just as you say, wrapped individually in cloth is good.