It looks like a photo would squeeze into the Interactive Family Tree with less modification.
That add-on used the Topola viewer. So you could submit a feature suggestion ‘issue’ to Prezemek Więch on his GitHub issue tracker
For the “Graph” Chart View add-on, Gary Burton appears to have requested suggestions be submitted via the Gramps bug tracker (powered by MantisBT)
Note that neither of these are Reports. So, if you wanted output (hard copy, including PDF; or to include it in a website generation), you might want to look through for a Report that could be adapted in the same way.