You've probably heard it many times that visual content drives engagement (read more traffic and conversion). Just a month after the introduction of Facebook timeline for brands, visual content - photos and videos - saw a 65% increase in engagement. Are you sure your site's images are good enough to drive traffic?
It's high time to re-consider image use on most websites, as the standards of what's good and what's not have significantly changed since the 1990s (time when stock image sites started to gain their popularity). Images for the sake of images are not a good practice anymore.