drawing bounding box for images

    I have a code below,in this i want to draw bounding box for each image,plz tell how to get coordinates and draw bounding box

siz = 64;
          bs = siz;                           
          Original =  myimage; G =  myimage     ;                  
          nob = (r/bs)*(c/bs);                 
          in =0;  
          kk=0;
          for i=1:(r/bs)
             for j=1:(c/bs)
     myima8(:,:,kk+j)=G((bs*(i-1)+1:bs*(i-1)+bs),(bs*(j-1)+1:bs*(j-1)+bs));            

               figure,imshow(myima8(:,:,kk+j))%%%have to draw bounding box 
               end
               kk=kk+(r/bs);                    
            end

            figure;imshow(G);