Fire tracking pixel on successful form submission

Is there a way to fire a tracking pixel on a successful form submission? Would something like this work?

Instead of this:
on_sent_ok: “pageTracker._trackPageview(‘/mysite/thank-you.html’);”

Will this work?
on_sent_ok: “pageTracker._trackPageview(‘<img src=”pixel.gif”>’);”

If not, is there another way to fire a unique pixel for each unique form?

http://wordpress.org/extend/plugins/contact-form-7/