Research conducted by Dan Zarrella, HubSpot’s social media scientist, did some research that found that Twitter users like to retweet images uploaded to pic.twitter.com get the most attention.
Tweets with images uploaded to pic.Twitter.com were nearly twice as likely to be retweeted while the use of Twitpic increased the odds by just over 60%. On the other hand Tweets that used Facebook or Instagram links were less likely to be retweeted. In all four of cases, I found a 99% confidence interval assuring us of the reliability of these results.
Here is the infographic of the results
Any thoughts on why this bias against Facebook images?