Layout of the active Image

Greetings,

Can someone please help me by giving me some suggestions about how to layout the active Image. e.g, when I click a Image , I can sub-layout this active image into pieces just like when clicking the Layout Icon , I can divide the whole viewer into the number of pieces I’ve selected.

Now I just didn’t figure out how to divide one Image into pieces(for example, 4 or 6 images)

Thanks in advance,
Jacob