Use a iOS Imageset inside a XAML view file (PCL-Project)

Hello,
I am trying to use in the iOS-Project instead of a normal BundleResource PNG-file a Imageset with more resolutions.

In the moment I have a PCL-Project as shared platform between Android and iOS.

The XAML head looks like:

<?xml version="1.0" encoding="UTF-8"?>
<ContentPage
    xmlns     ="http://xamarin.com/schemas/2014/forms"
    xmlns:x    ="http://schemas.microsoft.com/winfx/2009/xaml"
    x:Class    ="TreeWatch.MapMenuContentPage"
    xmlns:local="clr-namespace:TreeWatch;assembly=TreeWatch"
    Title      ="Menu"
    Icon       ="HamburgerMenuIcon.png"
    StyleId    ="MapMenu">
…

Can someone help me with this?

PS: If more information are needed just say it :-)

Greetings
Ron