MainPage.xaml

<?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="SelectMultiIpleImagesApp.MainPage"
			 xmlns:flv="clr-namespace:DLToolkit.Forms.Controls;assembly=DLToolkit.Forms.Controls.FlowListView"
			 xmlns:ffimageloading="clr-namespace:FFImageLoading.Forms;assembly=FFImageLoading.Forms">
	<ContentPage.Content>
		<StackLayout Padding="20">

		 <Button TextColor="White" BackgroundColor="Blue" Text="Select From Gallery" Clicked="Handle_Clicked"/>
			
		 <flv:FlowListView FlowColumnCount="3" x:Name="listItems" 
						SeparatorVisibility="None"
						HasUnevenRows="false" RowHeight="100" >
					<flv:FlowListView.FlowColumnTemplate>
						<DataTemplate >
					       <ffimageloading:CachedImage  DownsampleToViewSize="true" AbsoluteLayout.LayoutFlags="All" HeightRequest="100" AbsoluteLayout.LayoutBounds="0,0,1,1" Source="{Binding .}"  Aspect="AspectFill" HorizontalOptions="FillAndExpand">
					       </ffimageloading:CachedImage>
						</DataTemplate>
					</flv:FlowListView.FlowColumnTemplate>
			</flv:FlowListView>
		</StackLayout>
	</ContentPage.Content>
</ContentPage>