private void OpenImage(Bitmap image)
{
// close previous image if any
CloseImage();
// open new image
imageSize = image.Size;
pictureBox.Image = image;
pictureBox.Size = new Size(imageSize.Width + 2, imageSize.Height + 2);
imageSizeLabel.Text = string.Format("{0} x {1}", image.Width, image.Height);
ClearEstimation();
UpdatePictureBoxPositon();
EnableControls(true);
}