Beyond their search engine optimization purposes, "alt text" performs two roles:
- when an image is missing or slow to load, most internet browsers display the alt text upon rollover
- for visually impaired users, audio browsers use alt text to convey the title of the image
In the source code of your webpages, alt text is placed within image tags and looks like this:
<img src="imagename.jpg" alt="Write Your Image Title Here">
Here are a couple of examples:
<img src="drunk-driver.jpg" alt="Drunk Driver">
<img src="bottlenosed-dolphins.gif" alt="Bottlenosed Dolphins">
When determining the topic of a webpage, search engines give a little bit of weight to the words associated with images, so it's a good idea to use your primary and secondary keyphrases in image alt text, image names, and visible image captions.
So, when your webpages include unique images, use that as an opportunity for search engine optimization. For instance, if your primary keyphrase is "solar oven," then:
- alt="EnviroLiving Solar Oven" is better alt text than alt="Copyright EnviroLiving Inc."
- solar-oven.jpg is a better image name than elso200712.jpg
- EnviroLiving Solar Oven is a better visible image caption than none at all
However, easy does it:
- Using the same alt text for each image on a page will send a red flag to search engines.
- Don't annoy people using audio browsers or misidentify images for the purpose of stuffing in a few extra keyphrases.'
- Never assign alt text to a blank, hidden, or primarily decorative image
