Search Engine Optimization (SEO) is not all about optimizing your written content and the inner workings of your website. With many websites relying heavily on multimedia content such as images, it is also important to take some additional steps to ensure that your visual content reaches the search engines as well.
Alt Attributes and Captions
Information related to your images may be provided by using the alt attribute, a small piece of HTML code used to specify alternative text to accompany images, text and other content. Most modern Web browsers render the text provided in the alt attribute in the form of a tooltip which appears when the viewer moves the mouse pointer over the image. The alt attribute is not just for SEO, however – it also comes in handy for the visually impaired, since they can use screen readers to read out the text describing the image. The alt text also comes in handy if the image cannot be displayed for any reason, since most browsers will still render the alt text in place of the image if this is the case. All of the images on your website can and should have distinct alt attributes.
In situations where you use an image to link to another webpage, the alt attribute text will be treated in exactly the same way as the anchor text displayed in place of a standard link. Nonetheless, it is wise to rely more on text links than image links, simply because they tend to be more obvious to your readers. Sites which rely heavily or only on image-based links are likely to hinder your website’s navigation.
When filling in your alt attributes, avoid keyword stuffing and keep the image descriptions down to a few words – a single short sentence should be sufficient. The search engines will be more likely to penalize your content if you have excessively lengthy alt text with lots of key words and phrases included.
Including a brief descriptive caption with each of your pictures helps search engines with their categorization process as well. Many image searches include this caption next to the thumbnail and can further bring in additional website traffic.
Do not neglect the importance of your image filenames either. Use clearly readable filenames which describe the image in one or two words, since doing so will make them easier to find in image-based search engines such as Google Image Search. Avoid using generic filenames, such as picture1 or image1 etc. If you have a huge inventory of images on your website, you may be tempted to automate the image naming process, but doing so may also cause them to be poorly optimized for the search engines. You should also avoid very long filenames.
Consolidating Your Images
Another useful tip for optimizing your images for the search engines as well as making website administration easier is to store all of your image content in a single directory rather than having them spread out across the file structure of your FTP server. For best results, consider having a dedicated image directory in the root directory of your website such as the following: example.com/images. Finally, stick to using Web-friendly images such as JPEG, PNG and GIF. Avoid uncompressed formats such as BMP, since they consume a great deal of bandwidth and take far longer to load up.
Google also supports image sitemaps, and using them will increase the chances of your images showing up in the search results when a relevant query is entered. Image sitemaps are extensions for normal sitemaps, and you can make use of them by adding image-specific tags to your sitemap. While you can edit your sitemap manually by editing the sitemap.xml file typically stored in your website’s root directory. If you don’t already have one, you should create one. However, by far the easiest way to create and edit a sitemap, including adding the image-specific tabs, is to use a third-party tool to automate the process. Many content management systems have a sitemap generation feature or a plug-in available which provides this. Additionally, you can also create an entirely separate sitemap for listing your image content.
Google recognizes various image-specific sitemap tags including ones providing descriptions, URLs, captions, geographical locations, titles and copyright information. Only the first two are required, however.
Using these techniques will help drive in additional valuable traffic to your site that you might not otherwise have realized you were missing out on.