Posted to Volacci's blog on July 26th, 2011

4 Tips for Image Optimization - Image SEO


Images, unlike text, do not say anything to the search engine crawlers when they inspect a site. They do not have a voice, they are silent. However, with the help of some photo editing footwork, some basic HTML and some keyword research, you can give your images a voice and make sure the crawlers know exactly what the images are about. Here are some common but still-important image optimization tips.

The Volacci production team threw these points together today while drafting an in-depth, on-page SEO audit for one of our clients. Editorial collaboration at its finest :-)

1. Compress Images
Many jpegs on the web can be compressed to an even lower image quality without compromising visible quality. In Photoshop, Save for Web, select jpeg and set image quality to 70 percent. This will “blur” the image a bit, but not so much that the eye can detect it on a computer screen. Some say you can safely go down to 60 percent, some say 50 percent. Photoshop lets you preview the image at the lower quality level before you save it, so play with the percentages before sending the photo live. Remember to rename your file before you save the optimized version, else you’ll loose your original full quality image.

2. Optimize File Names
Some CMSs rename files to meaningless drivel when they are uploaded. In Drupal, the FileField Paths Module allows users to manually change this drivel into a keyword-rich file name before sending live. You better believe this will positively affect your site's SEO because search engines crawl file names in URLs and take meaning from them.

3. Optimize and Include Alt Tags
Once used to tell vision impaired users what an image was about, the alt tag is now a common on-page location for relevant keywords. Alt attributes are pieces of information embedded in image HTML that communicate meaning to search engines. An alt tag looks like this in the image HTML:

4. Optimize and Include Title Attributes
A title attribute is also an extra piece of information in image HTML to tell search engines what an image or link is about. It is used in SEO as a place for a short, keyword-rich description. It gives an additional voice to links and photos, serving as a supplementary tidbit to the file name and alt tag. It looks like this in the code.

As we all know, there are no silver bullets in SEO. Each of these image optimization components work together to communicate meaning to the search engines. In the above example, the targeted keyword "Drupal SEO" is used three times just in the image code. That could be huge, especially if done for images on every new content page.