Callback when image is loaded in Xamarin Forms

I have a Listview of Xamarin forms. The content of each cell in the list is text and one or more images. I search for a way to detect when everything in a cell has finished loading. My idea was to use the IsLoading property of Image. The image source is the URL url.

Here is the code for the FlexLayout that loads the list of images:

 <FlexLayout  AlignContent="Center" AlignItems="Center" Direction="Row" JustifyContent="Center" Wrap="Wrap"  VerticalOptions="FillAndExpand" HorizontalOptions="FillAndExpand" x:Name="media"   Grid.Row="1"  Margin="0,10,0,10" BindableLayout.ItemsSource="{Binding Media}">

        <BindableLayout.ItemTemplate>
                    <DataTemplate>

                              <Image x:Name="img" Source ="{Binding Url}" HeightRequest="{Binding ListHeigth}" WidthRequest="{Binding ListWidth}"  Aspect="AspectFit" VerticalOptions="FillAndExpand" HorizontalOptions="FillAndExpand" />

                    </DataTemplate>
        </BindableLayout.ItemTemplate>
 </FlexLayout>

I haven't found a way to bind the IsLoading property using XAML. As a list, I don't know how to use this attribute in each element:

img.PropertyChanged += (sender, args) =>
        {
            if (args.PropertyName == "IsLoading")
            {
                //do somink
            }
        };

How is the IsLoading property in Xaml bound? Or is there some other callback to detect that all the content of the cell is loaded?

thank you very much.