Incorrect width and height after graph.create and graphprototype.create

Options height and width isn't mandatory and if not set it in graph.create
Default values is "0"

After resave in frontend

Warning. Incorrect value for field "Width (min:20, max:65535)": must be between 20 and 65535.
Warning. Incorrect value for field "Height (min:20, max:65535)": must be between 20 and 65535.