Having or inserting at least one relevant image at your blog post, no matter what the topic or how long the article is, is highly important if you want more traffic and attention. I listed few tips below in case you wanted more info about how one relevant image can bring avalanche of hits and natural links to your article or post.
Search Engine Exposure
Search engines of today do have a powerful image indexing capability that enables them to give lots of images at their image search engine result page. Google image search, for example, is a huge traffic driving engine. You might miss the chance of getting seen at their result page if you don't have any image at your post at all.
Natural Links Resulting To Ranking And Traffic
Images at your blog post, especially if it's original and a property of yours, can give your blog or your article great links that can translate into ranking and traffic.
Your image might go viral at Pinterest, a huge image social media network that drives quality and targeted traffic to the image’s original source. That Pinterest image virality will result into lots of links (via repins) and traffic. Search engines like Google will consider this as a good signal and might place your article or blog in a higher position for the keyword or topic you are targeting at.
That is just for Pinterest alone, there are lots of social networks and media out there that might use and borrow your image in return of links and traffic.
If you have something to add with the above information, feel free to add them out at the comment section. Would love to hear something from you.