The search engines only try to emulate what visitors to a web site would like to see and therefore images play an important role.
Using pictures in your WordPress blog posts increase the quality of your articles as well as the search engine value of your posts.
It can be quite time consuming to find pictures that are related to your post and if you have to purchase each picture you quickly go beyond your budget.
What you can do instead is head over to Flickr and search for pictures that are related to your posts and that may be used free of charge even if you are using them for commercial purposes.
While you can do all these things manually it’s much faster to do it with a plugin.
Introducing WP SEO PIX
The ultimate WordPress Picture plugin.
WP SEO Pix is an ultra lightweight plugin designed for the current and future versions of WordPress.
It literally takes only minutes to install WP SEO Pix.
From then on you can just write your blog posts and whenever you need an image just click the little *symbol to active the picture plugin.

WP SEO PIX lets you quickly find images that are related to your post. All images that the plugin offers have a creative commons license and may be used commercially. Each picture links to the appropriate license.
Let’s look at an actual example of a picture in a WordPress blog post:

And here is the same picture if you look at it from within the WordPress blog in html view:

This all might look a little confusing to you but all these things are very important aspects of SEO for images:
Correct attribution and
Display of license
Alt- tag contains description
File name contains description
Descriptive title of image
Picture has a descriptive caption
The pictures are also cached on your site. That means you are not depending on Flickr - your web site will always look perfect without any broken images.
Through the use of the WP SEO Pix plugin your blog posts can get a boost in their search engine rankings. Additionally your posts can be found when visitors search for images. Depending on your niche the image traffic can be enormous.
Another advantage of pictures in your posts: Posts with pictures usually have a much lower bounce rate which in return will give you an additional boost in rankings.
Here are a couple testimonials from customers (prior to launching WP SEO Pix here I released it on the Warriorforum):

Never Again Pay For Pictures
Never Again Pay For Pictures