Thanks for your reply. I have updated my signature as suggested, and included the version of Home Designer Pro that I'm currently using. (I usually update it each year when the new version is released.)
I have tried searching for the solution in the help function, but I'm having another search. Thanks for your suggestion to use a framed picture.
It would be awesome if the developers include the option of insect screens as a window specification option (just like happens with window treatments and exterior shutters) in a future release.