anchor with image

[eluser]pierpads[/eluser]
Hello to everyone!
I've got a problem with an anchor containing an image:

echo anchor('controllerPrivato/visualizzaPagina',img($banner_image));

where $banner_image contains the src and the id of the image.
The problem is: I need that when someone clicks on the image, it redirects on a specific page with a certain id_page (I have a separated variable for that id_page).

How can I append the page_id to this anchor? (controllerPrivato/visualizzaPagina) waits for a $_POST variable, is that possible to pass it such a variable by the anchor??

thank you very much for help.