Nothing would give me greater joy than producing a reprex, but I do not know how to get there. I know one can render PNG and JPG files within the htmlwidgets framework, and then I suppose hypothetically style the image with included CSS, but is that is the best approach? The magick package might be a better alternative, but I do not have much experience with that package.
My plan was to add various effects to an image of a plot--shimmers, sparkles, glitters, shadows, distortions, etc. Fingers crossed that it would scale to Shiny.