The header image or the featured image of a post is one the most important sales pitches to a potential reader to click on that post and read it. You’ve probably heard a million times that “a picture is worth a thousand words”. In this case that is absolutely accurate. Good head (I had to, I’m sorry) is important.
Lois Chiles, Dr. Holly Goodhead, Moonraker
Selling it to your client
When a person scans the main index of your website, (RSS Feed and mobile website if you have a header image in them in place), the image you have for a post, whether that is a featured image or a header image, is its sales tool. It is the only visual sales tool for that post.
Since that is the case, you should try to use the most eye-catching image you can get your hands on for the header and/or featured image.
Make your image work in favor of the post
To accomplish this, seek and use resplendent photos. These images should be:
The reason for an high definition image is because they are more detailed, brighter, and the finer points in the image are more pronounced. I previously spoke of where to obtain such images here: 5 Movie Photo, Celebrity Picture, and Movie Poster Resources.
2. An image that tells a story.
An entertaining story told in a picture (example: Mother’s Day (2010) movie trailer 2) foretells of an equally if not more entertaining story in the post. Even if that is not the case, the picture still wets the viewer’s appetite and their curiosity. That tantalization could result in a click.
3. An image that houses one or more of the project’s main actors or actresses.
Using an image with a notable star or comely individual aways draws the eye. If the viewer is a fan of that person or persons, they might click just to see what that person is up to.
A link to a view
Make sure (if you care about driving the most traffic possible to the post) that the header image is hyperlinked to the post so that when it is clicked, the post, not the picture, is brought up. The person viewing the image in the main index of your site might want to save the image to their harddrive. They may click on it to see the image by itself or to see if there is a bigger version of the image. Hyperlinking it ensures that the post is viewed when this happens, not the image.
If your RSS Feed is in Summary mode, your post’s header image (if its displayed in your RSS Feed) plays an even more vitale role because you do not have the surroundings of your site to sell the post or ancillary clicks. Google Feedburner pages all look the same. The only thing that sells the post in your feed is the picture that accompanies the post and the title of the post.
On the mobile website version of your website, a header image will make your post sparkle because so few websites on the mobile web have header images. Blogger users automatically have them but WordPress users do not. Going the extra mile to get that image up and running will help to differentiate your mobile posts and sell your posts.
And always, remember
Optimize whatever images you use in your post, even in the header. You can find advice on this here: Using SEO optimized Images in your Posts to Increase Pageviews and here: 5 Ways to Optimize Images for Increased Pageviews and SEO.