assign rgb to 3d array

How do I give color to a specific row, col in my 3D matrix 321x481x3 uint8 ?

 image(row,col,:) = [0, 0, 255];

does not work

[KSSV]

Show the complete code which you tried...image(row,col,:) should work.

[Adam]

Also saying 'does not work' is no use to anyone. Do you mean it gives an error (if so give the full error message) or that it doesn't give the answer you expect or something else?

There's not much point asking a question if you can't be bothered to give the obvious relevant information!