How to find the exact index(row, col) of a maximum value in a matrix?

I want to find the maximum value in an image, I tried to find its index and I found it after converting the image matrix into a vector. How can I find this value in a matrix? and then plot it over an image?

Answer 1

[KSSV]

Let I be your image.

[m,n,p]  = size(I) ; 
x = 1:n ;
y = 1:m ;
[X,Y] = meshgrid(x,y) ; 
[val,idx] = max(I(:)) ; 
imshow(I)
hold on
plot(X(idx),Y(idx),'*r')