Is it possibe to track impressions on banners present on external sites?

I have an ecommerce site and planning to recruit affiliates for marketing. There will be ad banners, which the affiliates would put up on their sites. So, I waned to know whether it is possible to track the banner impressions on the affiliate sites from my piwik installation.

Again, a side question, if its possible to track the clicks on affiliate links (incoming links) from my piwik installation.

Thnx & regards