private void ContextMenuImagesOpening(object sender, CancelEventArgs e)
{
var pictureBox = this.contextMenuImages.SourceControl as PictureBox;
if (pictureBox != null)
{
var mode = pictureBox.SizeMode;
this.contextImageNormal.Checked = mode == PictureBoxSizeMode.Normal;
this.contextImageCenter.Checked = mode == PictureBoxSizeMode.CenterImage;
this.contextImageStretch.Checked = mode == PictureBoxSizeMode.StretchImage;
this.contextImageZoom.Checked = mode == PictureBoxSizeMode.Zoom;
}
}