Change width and height of a map marker

I am having trouble on changing the map marker size on IOS. When I change the size of the picture, map resizes it to its default marker size.
The code is :
<NativeViewHost Margin=“0,0,0,0” Layer=“Layout” Alignment=“Center” Height=“480" Width=“390” Y=“40">

<MapMarker Label=“You are at” Latitude=“{LatitudeOut}” Longitude=“{LongitudeOut}” IconFile=“…/assets/eren.png” />
<MapMarker Label=“{userIdTarget} is at” Latitude=“{LatitudeRead}” Longitude=“{LongitudeRead}” IconFile=“…/assets/TBus50.png” />