That seems a question for the FastStone developer, if it isn't in the user manual or the help.
Be sure to tell them which of their 4 different programs (2 freeware, 2 shareware) your question is about. That might make a difference.
When trying to "save as" there is a useful feature "Recent Places". Alas this shows no list of the recent places I have been to. How do I configure this "Recent Places" to the %APPDATA%\Microsoft\Windows\Recent Items?
Many thanks to all who will invest time and talent to solve my question.