macOS Help: Running a method when image is clicked on!

I'm only really just getting started with xCode and interface builder, Im really enjoying it but please can somebody help me with this issue?

In Interface Builder I have created a image well which has a NSImage inside.
When the image is clicked on, i want a method to run.
I have created a method:
- (IBAction)mouseClick: (id)sender;

I set that this method as a 'sent action' of the image well just like I would with a button. Although unlike a button the method does not run when the image is clicked on.

what do I need to do to make it behave in the same way. I have looked thru all the documentation and google searches for hours but cannot figure this out.

Please can someone point me in the right direction

When i connect either the Image cell or Image Well to my object the connection appears as a 'sent action. for both ImageCell and ImageWell.

Which should it be?, and why wont it call the method? The method is called of i connect it to a button.

Thanks