如何保持WPF元素在背景图像上的相对位置

I am new to WPF, so the answer to the following question might be obvious, however it isn't to me. I need to display an image where users can set markers on (As an example: You might want to mark a person's face on a photograph with a rectangle), however the markers need to keep their relative position when scaling the image.I am new to WPF, so the answer to the following