The study looked at a variety of types of posts, and found that 85% of the "most engaging Facebook posts" incorporated photos. In contrast, 3% of the most engaging posts incorporated video, 5% were status updates, and 7% were links. Furthermore, photo posts received 84% more link clicks that text-only or link posts.
The report suggests that this conclusion might challenge initial theories that using text-only posts could be a better Facebook strategy for businesses, versus the contradicting argument is that Facebook surfaces text-only posts in News Feeds more often than photos... Marketers who are using interesting images to their advantage can increase traffic to their websites with an included link.
Sources - A Picture is Worth More Than Any Words, ResearchBrief
Facebook yanks Instagram usage data from public view, C/Net
Photos on Facebook Generate 53% More Likes Than the Average Post [NEW DATA], HubSpot's Inbound Internet Marketing Blog