We wrote 4 reviews of 4 websites. We added 4 links to those 4 web pages on our homepage. 2 of the pages had an image on it and 2 of them had no images. The two reviews with a picture ranked better than the two reviews without a picture.
The 2 reviews that ranked the best weren’t the reviews of the most popular websites. The difference of web traffic between the 2 reviews with pictures and the 2 reviews without pictures was obvious. The reviews with pictures received twice of web traffic in comparison to the reviews without pictures.
We think that maybe the images themselves aren’t responsible for the ranking boost. We also added captions and alt text to the pictures. Also, the names of the picture files were related to the most important keywords of the page. At last, those pages were not from a stock photo database. They were not stolen from another website.
We can’t make many conclusions here but I think that this experiment can help you to determine whether images and images meta data are important in SEO.