public partial class MainForm : Form
{

public void videoImage(Image image)
{
    this.VideoViewer.Image = image;
    if (this.InvokeRequired)
    {
        this.Invoke(new MethodInvoker(delegate { videoImage(image); }));
     }
}

public void mapImage(Image image)
{
    this.VideoViewer.Image = image;
    if (this.InvokeRequired)
    {
        this.Invoke(new MethodInvoker(delegate { mapImage(image); }));
    }
}

}

public delegate void videoImageReady(System.Drawing.Image image);
public event videoImageReady videoImage;

public delegate void mapImageReady(System.Drawing.Image image);
public event mapImageReady mapImage;

// this is called from any thread
public void videoImage(Image image)
{
    // are we called from the UI thread?
    if (this.InvokeRequired)
    {
        // no, so call this method again but this
        // time use the UI thread!
        // the heavy-lifting for switching to the ui-thread
        // is done for you
        this.Invoke(new MethodInvoker(delegate { videoImage(image); }));
    }
    // we are now for sure on the UI thread
    // so update the image
    this.VideoViewer.Image = image;
}

if (this.InvokeRequired)
{
this.Invoke(new MethodInvoker(delegate { videoImage(image); }));
return;
}