gtkcellrenderer pixbuf + togglebutton

[z2274394 student unsw edu au]

Dear Noble Gtk developers,

I have a cellrenderer pixbuf in a gtktreeview. I want the pixbuf to have
checkbox functionality such that when user moves mouse over pixbuf and
clicks...it wil change the pixbuf picture to resemble 'activated' state. When
user clicks again, it will return to the original pixbuf. How would I go about
doing this?

the api for cellrenderer has these functions:
gtk_cell_renderer_render
gtk_cell_renderer_activate

but I do not understand how to use them to acheive the above purpose. Any help
is much much appreciated.

With many thanks
gangas