According to the first reports from online advertising campaigns that run on our customers, Facebook's "Carousel ads" pay 10 times more than the ordinary ads in the same social network!
As mentioned in a Facebook press release:
[...] we introduced the carousel format for Facebook ads (referred to as Multi product ads), which lets advertisers showcase multiple images in one ad. Since then, advertisers have seen carousel link ads drive 30 to 50 percent lower cost per conversion and 20 to 30 percent lower cost per click than single-image link ads.*
Facebook Carousel items:
Note: The image must not contain more than 20% of text. Check the rate of text to images, using the special tool of Facebook, here.