Site like Google image search frame a website behind an image belonging to that website when displaying these to a visitor and attempting to bust that frame can hurt you, here's how
- Increased bounce rate(10%+) when someone looking at the image dislikes being taken from Google. Instant backpage.
- Negative impact on all related metrics. e.g. time on site, pages viewed etc.
You may notice in Google analytics that these frame busted visitors show up as 'direct visits' but if you remove the frame busting script they appear as 'referred by Google'. Removing the frame busting script will lower the number of visits to your site substantially between these two categories, perhaps in the order of 75%, but the damage being done to your stats is worse.
Good news, remove the frame busting script and all metrics will improve and, given enough time, the benefit should work out to an equal number of total visitors with a better track record for your site (which impacts traffic from Bing, Yahoo etc as well).
In having removed one such frame busting script a month ago the traffic lost has more than been replaced by natural and referral traffic from all three major search engines. In theory it sounds great to 'get more visitors' but if they don't appreciate being busted the effect isn't worth it. I suggest removing the scripts for a trial period of 3-4 weeks, if you use them, and seeing what happens.