Windows 10 Live Tile Branding Logo extremely small

I have the following problem. I create Secondary Tiles within my application and brand them with name and logo. Compared to other apps I have pinned the logo seems to be extremely small. I created the badge logo and all logos with targetsize with no border. Can anyone tell me which picture is exactly used for the branding logo?

The tile is created like this:

string tileId = "MySecondaryAppTile"
string displayName = "MyApp";
string tileActivationArguments = "MyApp activated from Secondary tile";

Uri square71x71Logo = new Uri("ms-appx:///Assets/Square71x71Logo.png");
Uri square150x150Logo = new Uri("ms-appx:///Assets/Square150x150Logo.png");
Uri wide310x150Logo = new Uri("ms-appx:///Assets/Wide310x150Logo.png");
Uri square310x310Logo = new Uri("ms-

TileSize newTileDesiredSize = TileSize.Wide310x150;

SecondaryTile secondaryTile = new SecondaryTile(tileId,
                                                displayName,
                                                tileActivationArguments,
                                                square150x150Logo,
                                                newTileDesiredSize);

 if (!(Windows.Foundation.Metadata.ApiInformation.IsTypePresent(("Windows.Phone.UI.Input.HardwareButtons"))))
 {
      secondaryTile.VisualElements.Wide310x150Logo = wide310x150Logo;
      secondaryTile.VisualElements.ShowNameOnWide310x150Logo = true;
      secondaryTile.VisualElements.Square310x310Logo = square310x310Logo;
      secondaryTile.VisualElements.ShowNameOnSquare310x310Logo = true;
 }

 secondaryTile.VisualElements.ShowNameOnSquare150x150Logo = true;

 secondaryTile.RoamingEnabled = false;

 Windows.Foundation.Rect rect = FloorPage.GetElementRect((FrameworkElement)sender);
Windows.UI.Popups.Placement placement = Windows.UI.Popups.Placement.Below;
bool isPinned = await secondaryTile.RequestCreateForSelectionAsync(rect, placement);

The Tile notification like this:

TileContent tileContent = new TileContent()
{
   Visual = new TileVisual()
   {
        **Branding = TileBranding.NameAndLogo**,

        TileMedium = new TileBinding()
        {
             Content = CreateTileBindingContent()
        },

        TileWide = new TileBinding()
        {
             Content = CreateTileBindingContent()
        },

        TileLarge = new TileBinding()
        {
            Content = CreateTileBindingContent()
        }
    }
};
TileNotification notification = new TileNotification(tileContent.GetXml());
TileUpdateManager.CreateTileUpdaterForSecondaryTile(tileId).Update(notification);

To be shure I mean the following logo:

It will use Square44x44Logo as Branding logo. So make sure your assert file looks right(e.g. the transparent part of your logo should be as less as possible).