How can I overlay a timestamp onto an image?

Thus far, I've tried creating a timestamp, making it into an image using code from http://www.mathworks.com/matlabcentral/fileexchange/25772 and overlaying it using the following code:

             get timestamp

             datetime = clock; % get date and time
             imgName = [num2str(datetime(2),'%.02i') num2str(datetime(3),'%.02i') num2str(datetime(1)-2000,'%.02i')];
             imgName = [imgName '_' num2str(datetime(4),'%.02i') '-' num2str(datetime(5),'%.02i') '-' num2str(datetime(6))];

            %overlay timestamp onto image
            obj = Other_MEM_Text2Im(imgName, 342, 20, [1 1 1]);

            scene = img_out;
            result = scene;
            rowshift = 0;
            colshift = 0;
            result((1:size(obj,1))+rowshift, (1:size(obj,2))+colshift, :) = obj;
            img_out = result;

However, whenever I run this code, the timestamp image doesn't show up at all. Is there any way to get the timestamp image to show up? Or another way to get the image with a timestamp on it? Thank you!