See the question and my original answer on StackOverflow

You're supposed to use the Visual Studio Image Service and Catalog. However this document doesn't explain how to get the image for a given file.

You'll have to use the IVsImageService2.GetImageMonikerForFile Method. As described in the document, you can get GDI/Winforms, Win32 or WPF images. Here is a sample code that does it for WPF's BitmapSource:

public static async Task<BitmapSource> GetWpfImageForFileAsync(AsyncPackage package, string filename, int width, int height)
    if (package == null)
        throw new ArgumentNullException(nameof(package));

    var svc = (IVsImageService2)await package.GetServiceAsync(typeof(SVsImageService));
    if (svc == null)
        return null;

    var mk = svc.GetImageMonikerForFile(filename);
    var atts = new ImageAttributes
        StructSize = Marshal.SizeOf(typeof(ImageAttributes)),
        Format = (uint)_UIDataFormat.DF_WPF,
        LogicalHeight = width,
        LogicalWidth = height,
        Flags = (uint)_ImageAttributesFlags.IAF_RequiredFlags,
        ImageType = (uint)_UIImageType.IT_Bitmap

    var obj = svc.GetImage(mk, atts);
    if (obj == null)
        return null;

    obj.get_Data(out object data);
    return (BitmapSource)data;

Here is how you can use it for example at package initialization:

public static async Task InitializeAsync(AsyncPackage package)

    // note a valid extension is sufficient
    _pngBitmap = await GetWpfImageForFileAsync(package, "whatever.png", 32, 32);

   // etc...