Resizing external image in Rmarkdown: html vs. ioslides output -

i'm using external images in rmarkdown document meant rendered ioslides , need resize them.

doing html way works both when knit ioslides , html_document.

<img src="image.png" style="height: 200px"/>

doing markdown way below works when knit html_document not when knit ioslides (i.e., image isn't resized).

![](image.png){width=200px}

my question is: how can make markdown resizing approach work when output ioslides?

TY