I tried that, It did not work.
Checking the Luxor.jl and ControlSystems.jl packages, they use different approaches to get the figures in the gh-pages branch and rendered in the final HTML. Luxor.jl uploads the figures directly to the assets/figures folder and ControlSystem runs all examples as doctests and apparently, the figures go to the gh-pages branch.
I am wondering why @example does not save figure files.