Images are a part of any good web site, but they can hurt you in the search engine rankings if they're not set up correctly. Also, you may have already noticed that you do not have to do an image search to pull up images in your search results. Images are becoming part of the normal search results on all of the search engines. Make sure your site is ready to rank with these important tips about optimizing the images on your web site.
File Name: The first step to optimizing the images on your site is to check the file names. Many, you may find, are titled things like "pic 1", "2.gif" or "3.jpg". You can rename the images so that the file names are actually descriptive of the image details. Avoid generic names that confuse search engine spiders and users alike.
Alt Attribute: Many people have security settings on their browsers to inhibit the display of images for one reason or another. Some may be to protect them from sites they do not trust while others do it just to increase their internet speed. The alt attribute is a message that displays in place of the image if it is blocked from view. The alt attribute should tell what the image is about. This message is also the anchor text for clickable images.
Clickable Images: Keep clickable images to a minimum. They can be confusing to search engines, especially if they are the only means of navigating around the site. This goes for images or graphics such as drop-down menus that are used for navigation. Use plain, organized text for navigation.
Robot blocked images: A lot of older sites and some of the newer ones with unaware webmasters are set up with the images blocked by their robots.txt files. These are useful for keeping certain things from being crawled and indexed on your site, but now that images are becoming important to search engine rankings, you may want to move your images to a new folder where they are not blocked from being ranked. Having your images all in one place helps the search engines to index them, as well.
You can use Web Analytics or Google Website Optimizer to see which image changes will do your site the most good. Since images are becoming more and more important on the search engines, you may want to work with a search engine marketing company to keep your images up to date.