//Creates update data with images that were just saved
FlipTileData ftd = new FlipTileData()
{
    Title = String.Empty,
    BackTitle = String.Empty,
    Count = 0,
    SmallBackgroundImage = new Uri(string.Format("isostore:{0}", sfname), UriKind.Absolute),
    BackgroundImage = new Uri(string.Format("isostore:{0}", lffname), UriKind.Absolute),
    BackBackgroundImage = new Uri(string.Format("isostore:{0}", lbfname), UriKind.Absolute),
    WideBackgroundImage = new Uri(string.Format("isostore:{0}", wffname), UriKind.Absolute),
    WideBackBackgroundImage = new Uri(string.Format("isostore:{0}", wbfname), UriKind.Absolute),
};

//Updates secondary tile
var secondaryTile = ShellTile.ActiveTiles.FirstOrDefault(x => x.NavigationUri.ToString().Contains("tile=1"));
if (secondaryTile != null)
{
    secondaryTile.Update(ftd);
}
else
{
    ShellTile.Create(new Uri("/MainPage.xaml?tile=1", UriKind.Relative), ftd, true);
}