The AdBlock for Safari App has got two Safari App Extensions: one for basic ad blocking functionality, and a second one (comes together with the app) that sets an icon in Safari to manage ad blocking details for every single page. With this icon (at least in older versions – I'm not sure whether or not it's still there.) you could block elements of the page like pictures, frames etc. from beeing displayed or printed. That seems to be exactly what you are looking for.