What is image alt text?

Alt text stands for “alternate text”. It was created to give users “alternate” information if for one reason or another they couldn’t view an image. So if a visitor has a slow connection, there’s an error in the image source, or they are visually impaired (requiring the use of a screen reader), they’ll still be able to see or hear the alternative text (as long as it’s being used). It also gives search engine crawlers the ability to index images properly.

Example of an Alt Tag: <img src=”hamburger.jpg” alt=”hamburger with dripping BBQ sauce on a bun with bacon, onions, lettuce, and tomatoes.”>

Alternative text is on the list of on-page seo factors that contribute to ranking increases in Google and Bing.

Alt Text Best Practices

• Be Specific – when creating alt text for an image be as specific as possible to convey what the image is all about. Do you think the alt text for the image above should be hamburger? I think we can do better than that. How about alt=”hamburger with dripping BBQ sauce on a bun with bacon, onions, lettuce, and tomatoes.”
• Be Concise – screen readers stop at about 125 characters. Keeping it under that limit is recommended.
• Be Thorough – all of your images should have alt text. Don’t limit their use to photos. Alt text should be added to buttons and other design elements to describe their function.
• Be Sure to Add Keywords – if an image on your page is relevant to the keywords you are targeting on the page, don’t be afraid to add them. Alt text gives you another opportunity to let search engines know that images on your page are relevant to a particular search query. Don’t stuff keywords. One descriptive phrase will do.