custom shape image frame

Hi, I need a little help with image frames with custom shape. I created the upload zone from svg file with "waves" on top but when I upload image it has straight line on the top (without waves). In the attached files left side is what I am able to to in FPD and on the right side is what I would like to get. And on the buttom is my setup from admin panel.

I also tried to play with masks, maybe I just dont know how to set it up properlly.

Please can you give me some advice?

Thank you, Martin.