Approximately ten bajillion people have written about why you, intrepid blogger, need to include pictures in your blog posts. I know this because a quick Google search on "why should I put pictures in blog posts" will give you more results than the grains of sand on the beach or the number of alien brain parasites that inhabit the skulls of the MSNBC prime time roster.
These articles (blog posts, posts, what have you) exist for one simple reason: People are more likely to click on a post with a picture than one without a picture. Smart people have done or commissioned studies on this point and, though none of the studies agree on the exact number, they all agree that posts with pictures get more clicks.
As nice as clicks are, though, your goal as an activist probably isn't to draw a herd of indiscriminate readers who happened to like the cute cat picture you stuck at the top of your post [Ahem...]. If it is, God bless you. Grab an inexpensive membership to a stock photo site and go to town. However, if your goals are to bring people to your site who want to engage usefully with what you write, share your posts with their family and friends, and bring others to your site, you need more.
Not just any photos will do. You need good photos.
Fortunately, good photos aren't as difficult to find as you may think (I'll give you a couple great places to look in Part II, which will post here soon). Here are three things that differentiate a good photo from the average.
1) Good photos create resonance. In their book The Impact Equation, Chris Brogan and Julien Smith wrote about Echo, which they defined the connection between you, the writer, and an individual reader. The more Echo you can build with each of your readers, the more emotional resonance you create and the greater the connection. All of us prefer to get our news and opinion from people we not only trust but like. Echo builds both, and pictures go a very long way toward creating a strong connection between you and the people you want to reach.
Consider an article about the effect the federal deficit will have on the next generation. You could use a stock chart that shows the increase every year or a graphic of a large pile of cash. How much Echo does that create, though? On the other hand, you could use a picture that better suits the tone of your article (funny for a snarky article, for instance) or one that makes an emotional point to reinforce the facts of your article (perhaps an old photo of poor children during the Great Depression). Either choice would resonate more directly with a reader. Remember, the more resonance you create, the more you're likely to have engaged readers who will share your material. (tweetable)*
2) Good photos make your posts more shareable. These days, you can share one piece of new media content on several different platforms with the same ease Miley Cyrus gets a headline in the Daily Mail. Indeed, most bloggers have their "go-to" platforms on which they repurpose their blog posts with little more than an extra click or two. Mine are Twitter and Pinterest. Others prefer Facebook, Tumblr, or Google+**. Everyone has their favorites and a clever blogger will make sure their posts are easy to share in as many places as possible. (tweetable) Good photos makes your blog posts more easy to share. They also make your photos more easily noticed on other platforms, thanks to a clever little innovation called the "social snippet". Notice how prominent the photo is on each snippet (and how close that photo is to the means to share it elsewhere).
Remember, though, we're talking about good photos, so let me belabor this point just a bit longer. No one will pin a boring stock photo to their "Most Incredible Photos I Ever Seen" Pinterest board. Generic Money Bag Guy up there is not going to get you a bazillion upvotes on imgur or Reddit. To paraphrase King David, a blogger that wants to be shared must make his work sharable. (tweetable) Find a good picture to bring your post home and your readers will make sure it gets shared far and wide.
3) Good photos help you flex other creative skills. I bet you thought all you really needed to be a good blogger is writing talent. I sure did when I started my blog over 9 years ago. I was wrong. Blog readers have developed more sophisticated palates and the proliferation of blogs (100,000+ new blogs every day using WordPress alone) mean you're a small fish in an immense pond. Good bloggers must bring a plethora of skills to the table, including art and layout skills and an eye for an arresting visual image. (tweetable) Those skills come only with practice and, as with any skill, the more practice you get the better you will be. A one-dimensional blogger is a blogger who will soon be without readers - as starved for traffic as the town of Radiator Springs after the highway went through.
You also get a bonus with practice, in the form of other skills that will also improve. The ability to see what makes a good picture can also empower you to take good pictures of your own. You can learn how to enhance or "remix" pictures. You can learn good captioning skills, (or, in the case of LOLCat captions, you can haz skilz) but I'll cover more on all of that in Part II. What's important to remember is that choosing good photos to match your good blog posts will work out creative muscles you don't even know you have right now, but you'll be glad are strong later on.
Pictures and blog posts are natural buddies. They go together like a former child actor and crazy. Your job as a blogger is to match a good photo with your good blog post. How do you do that? Where do you find good photos? Stay tuned. Part II is right around the corner.
*Ever wonder what that (tweetable) thing is? Click the link. You'll get a separate tab with a tweet populated with a quote and a link to this article. Like the quote? Just click and tweet. Easy-peasy!
**Yes, G+ fans exist. Lots of them. Ask Guy Kawasaki.