For SEOs, pretty pictures can do far more than just appeal to their sensitive sides; they can also help move up in the search rankings and drive traffic to their websites if they know what they're doing.
It's important to note that optimizing images does more than just make it easier for users to find them in a Google Image Search (although that's probably the most important reason for doing it), but also because it increases the image's shareability and plays a role in helping trace the picture back to your site, and on today's highly social Web, that can be beneficial.
But what does it take to optimize images for SEO? Well, just keep reading...
File Names
Since you've already done all of the hard work of keyword research (right?), you already know which terms your most sought-after audience is going to be searching for. Use this knowledge to drop those keywords into the image's file name when you're saving it to your server. Now, search engines can read those keywords and your images will begin to appear for related search queries. A couple of considerations you should note: If you're file name has more than one word, separate them by dashes (or hyphens) and not underscores. Also, Google recommends you only use common image file types, such as JPEG, PNG, GIF or BMP.
Alt Text
Because there isn't any inherent text content that search engines can scan, images are at a natural disadvantage when it comes to SEO. One of the best ways to combat this prevalent problem (and improve the user experience of your site) is to add an alt tag to an image in a Web page's HTML code that includes some helpful descriptive information about the content of the picture; and if you can slide some keywords in there naturally, all the better, but it certainly shouldn't just be made up of keywords. Make sure your alt tag text is as descriptive as possible, and if you're using a specific image as navigation to link to another page, also include text that is relevant to the page that it links to, as well.
Anchor Text
In the same vein, make sure that any text that you use to link to an image is both ranked for keywords and appropriately describes the image. Again, this isn't just appealing to search engines; it's also useful for your website visitors.
Page Placement
Once you've begun to optimize your images for the search engines, you can make them easier to find by placing the pictures next to or near keyword-related content on a Web page. Since search engines will be more drawn to these specific areas on a site, they'll be more likely to spot your image when they crawl the page.
Links
Getting a few inbound links that point directly to your image is another great way to garner it some attention from the search engines. These can come in the form of you leveraging your own network of Internet properties to provide links to the images, or by building links from outside websites and/or publishers in the same way that you would look for links to your site and content; so don't be afraid to ask your friends and business partners for links once in a while. Just make sure these links use targeted keywords (or at least a close variation of those keywords).
Rich Snippets
Using rich snippets will tag a single image to your website or business that will appear anytime someone searches for your brand. So if you have one that is highly related to or indicative of your company/site, add some snippets. It will help your listings stand out on the SERPs and can even increase your click-through rate.
Social Interaction
The real reason images are quickly becoming a valuable currency on the Web is because of the rise of social media and social networking sites, which make shareability one of the most important qualities of good content. Because of this, you should be distributing your already-optimized images on various social networks like Facebook, Tumblr and Google+, as well as image hosting services Flickr, in addition to putting them on your website. Many of these services, particularly Facebook, Tumblr and Flickr, will allow you to tag your images with keywords and/or descriptions or caption, meaning you can also use this opportunity to get your pictures noticed by targeted users. Just don't forget to find a way to include a link back to your website alongside the image (probably in the caption/description) so that you can also drive traffic from the social network, as well.