Xamarin.Forms Toolbar Item Icon Size

I have a Xamarin.Forms PCL project and I am trying to add a Toolbar to my App as below and my target platform is UWP.

<ContentPage.ToolbarItems>
    <ToolbarItem Icon="attach.png" Order="Primary" Priority="1" />
    <ToolbarItem Icon="camera.png" Order="Primary" Priority="1" />
    <ToolbarItem Text="Item1" Order="Secondary" Priority="1" />
    <ToolbarItem Text="Item2" Order="Secondary" Priority="2" />
    <ToolbarItem Text="Item3" Order="Secondary" Priority="3" />
    <ToolbarItem Text="Item4" Order="Secondary" Priority="4" />
</ContentPage.ToolbarItems>

I have added all icon sources to root folder of UWP project. When i run the app on Windows 10 Desktop, icons appears too small. Orginal size of the image is okay though.

I would be appreciated if someone know how to fix this.