image aspect ratio

[tdejaco]

Hi, I'm using bsselect within a RMarkdown html document to create a dropdown list. How can i fix the aspect ratio of the widget? With defaults, the widget width is adapting to my html window size nicely, but the height is not. I tried to use width and height options within bsselect(), but neither had any effect. On which level do I need to specify a fixed aspect ratio?

I'm new to Rmd and html widgets, sorry for such a basic question. cheers, thomas