// Return the aspect ratio (as Width/Height) of a bitmap or its placeholder as efficiently as possible
// Timing tests suggests this can be done very quickly i.e., 0 - 10 msecs
// While this is marked as virtual, there is currently no over-ride for getting it from a video.
// So it should only be invoked if we know the file is an image
public virtual double GetBitmapAspectRatioFromFile(string rootFolderPath)
{
return(BitmapUtilities.GetBitmapAspectRatioFromImageFile(this.GetFilePath(rootFolderPath)));
}