Well the operative word here is “need”. No you don’t “need” to use them but you “should” use them.
Why should I use images?
Having a good, relevant photo at the beginning of your post can help to make your post memorable. It seems most people are able to recall an image much easier than text so this is a logical reason to put an image near the beginning of your post.
Photos break up the text. Have you ever read a long post without any photos? It’s pretty dull. Having a couple short paragraphs and then a photo can really help to break up the post for a reader to digest before moving on to the next chunk of content.
When you use relevant photos in your blog posts you are able to help the SEO on your page. You can add tags to your photos in several different ways. Oracle Digital wrote a great post that gives you specific ways to add tags within the photo posts in WordPress to increase your SEO.
How many should I have per post?
This is a really a personal decision. I think in a short post (250-400 words) you should have one. You might be able to slip a few more. It all depends on the subject matter. Say, for instance you’re posting a recipe, you could post several photos, maybe up to 8 or 10, depending on how it relates to your actual post. But for a business blog that would most likely be way to many.
As a rule of thumb, I would say one photo per every 300 words or so.
Where do I get photos?
I like to use free photos when I can for the obvious reason, that they’re free. A great place to get free stock photos is stock.xchng and another one I use is MorgueFile. Both of these sites have tons of photos in many different categories. Whenever you use photos that you haven’t taken yourself be sure to read the rules of use and give credit where credit is due.
Photography is a hobby of mine so whenever I can take relevant my own photos I will. I love to see a blog post with original images just because it makes it more personal. I know not every site wants to portray a personal feel but I think for bloggers its a good thing.
The bottom line is photos enhance your blog posts and should be used.
Where do you get your photos? How do you use them in your blog?