placing png in indesign results in a white transparent layer over background

Importing a png file in my indesign file results in a white transparant layer over the entire page IF the background is a image. 

But when the background is a box with a fill color everything is oke if I add a png to it. Why is this because I want to use an image as a background but don't want the transparant white layer. 

I have added some pictures to show you what I mean. 

Thank you in advance.