3d Image Processing(Set one image on another image)

From your question, let's assume that you have two images:

1. Please try this code

(1) One is master (baseImage )image
(2) The other one is, Label image (topImage)

First, please overlay the topImage on the baseImage. If you need to show both images, set the transparency to lower value. Then, display the image where do you want it to display(whether it is on WPF or WinForms apps). Please do this before displaying the image on the fly.

public Image OverlayImage(Image baseImage, Image topImage, float transparency)
        {
            System.Drawing.Imaging.ImageAttributes ia = new     System.Drawing.Imaging.ImageAttributes();
            System.Drawing.Imaging.ColorMatrix cm = new System.Drawing.Imaging.ColorMatrix();
            cm.Matrix33 = transparency;
            ia.SetColorMatrix(cm);
            Graphics g = null;
            try
            {
                g = Graphics.FromImage(baseImage);                              
                Rectangle rect = new Rectangle((int)(topImage.Width * 0.1), (int)(topImage.Height * 0.2), (int)(topImage.Width * 0.8), (int)(topImage.Height * 0.6));
                // YOU MAY DEFINE THE RECT AS THIS AS WELL
                //Rectangle rect = new Rectangle(0, 0, baseImage.Width,      baseImage.Height, baseImage.Width);
                g.DrawImage(topImage, rect, 0, 0, topImage.Width, topImage.Height, GraphicsUnit.Pixel, ia);
                return baseImage;
            }
            catch (Exception ex)
            {
                throw ex;
            }
            finally
            {
                g.Dispose();
                topImage.Dispose();
            }
          
        }

2. I only make the above code for Format32bppIndexed format. As we know there are many image formats. If you want to use third party, please try this. It has Overlay and watermark functionalities which suite for your questions as well:
http://www.artuxsoft.com/[^]