//C# CODE
PdfSharp.Drawing.XImage _xImg = PdfSharp.Drawing.XImage.FromFile(@"C:\myTestImg.jpg");
_xImg.Memory.Close();
_xImg.Memory.Dispose();
_xImg.Dispose();

File.Delete(@"C:\myTestImg.jpg"); // this is where the exception accoures: IOException "The process cannot access the file 'C:\myTestImg.jpg' because it is being used by another process."

GC.Collect();
GC.WaitForPendingFinalizers();

wpfImage = new BitmapImage(new Uri(path));

this.wpfImage = new BitmapImage(new Uri(path));  // AGHACK

 BitmapImage temp;
 temp = new BitmapImage();
 temp.BeginInit();
 temp.CacheOption = BitmapCacheOption.OnLoad;
 temp.UriSource = new Uri(path);
 temp.EndInit();
 this.wpfImage = temp;

Using image As XImage = XImage.FromFile("C:\temp\locked_image.jpg")
  imageHeight = pageWidth / image.PixelWidth * image.PixelHeight
  gfx.DrawImage(image, marginLeft, marginTop, pageWidth, imageHeight)
End Using

this.wpfImage = new BitmapImage(new Uri(path));

this.wpfImage = new BitmapImage(new Uri(path), BitmapCreateOptions.None, BitmapCacheOption.OnLoad);