How to transform a part of picture to the button

Hi all,

Could somebody tell me if it's possible or not?

I have a picture on the slide and I need to do some areas of this picture clickable (to add triggers).

I found the long way (to add fully tansparent buttons ahead of these areas). But my mind tells me that it is much simplier to select the area on the picture and simply set it as a button (by clicking something). Does Storyline have such ability? How can I do this?