Centering Image in Merged Range

AHHHH - I was wondering why it wasn't showing up in the macro menu. Removed that and it popped right up. I did a quick Google search and understand the basic use of that command but im curious why you included it in the first place?

Also, it only seems to be working on the first range I use it on. I get an error saying there is no shape in the range if I try to execute it on a second range. In the attached it works as expected in range 1, but in 2 and 3 it insists there isn't a shape there. Any thoughts?

Thanks,
Simon