Hi Paul, welcome to VBForums.

The ZoomPictureBox allows you to set the Image to Nothing and to call its Invalidate method in much the same way as a PictureBox. In both cases, the image source file remains locked. The safest way to avoid this is to read the image as a Stream instead of opening it with Image.FromFile(filename) or New Bitmap(filename).
    Using stream As IO.Stream = IO.File.OpenRead(filename)
         ZoomPictureBoxName.Image = Image.FromStream(stream)
      End Using
The source file is closed at the end of the Using block, so you are free to delete it independently of the image.