Imagine that you’re browsing an eCommerce website on a slow internet connection. You want to buy a t-shirt, but you want to make sure it’s well-designed. The images on the page don’t load, so you need to read the alternative text (alt text) to understand the purpose of the visual content.
The alt text for the product reads:
Black t-shirt with white lettering, plain black t-shirt, black shirts for men, stylish black shirts for men.
Would you buy the product?
Probably not. You wouldn’t have enough information to make that decision, and the spammy nature of the alt text might discourage you from clicking the “add to cart" button.
Unfortunately, a lot of alt text reads something like this — and for non-visual users, that’s a big problem.
Here’s what’s happening: Alt text can be a powerful tool for search engine optimization (SEO). Google, Bing, Yahoo, and other search engines emphasize the importance of accurate alt text in their webmaster guidelines, and SEO services have certainly paid attention.
That has led to a common misconception: If your image alt text contains keywords that are relevant to your business, the picture will show up in image search. More search leads to more users, which will lead to more sales.
Here’s why that’s a myth, along with tips for writing alt text that improves experiences for real users.
Alt text is an SEO signal, but it’s not the most important signal
Search engines crawl content looking for keywords, and most search engines can’t crawl images without some help from content creators. To that end, alt text may be an important SEO signal. It shows search engines that your website contains visual content related to the purpose of each page.
However, there’s a clear limit. If alt text contains too many keywords, search engines may ignore it entirely — and if it doesn’t match up with other SEO signals, it’s not especially important.
In 2021, Google search advocate John Mueller noted that “alt text isn’t a magic SEO bullet.” And per Google’s Webmaster Guidelines, alt text isn’t the only tool that search engines use when evaluating visual content:
Google uses alt text along with computer vision algorithms and the contents of the page to understand the subject matter of the image. [Emphasis added.]
Generative artificial intelligence (A.I.) tools can accurately identify many images, and it’s a safe bet that Google and other providers are leveraging the power of A.I. to improve their search tools.
Ultimately, packing your alt text with keywords won’t help you rank for additional search terms. And if your alt text isn’t descriptive, the user experience suffers.
Think about users when writing alt text
Alt text isn’t just for search engines. For some users, it’s the best tool for understanding visual content.
People who use screen readers (software that converts text to audio) may not be able to perceive images. The alt text stands in as a replacement; if the alt text is vague, repetitive, or inaccurate, you’re telling these users that you don’t care about their business.
The Web Content Accessibility Guidelines (WCAG) require text alternatives for all non-text content. Those alternatives must be reasonably equivalent — in other words, if images don’t load, people should be able to use your website.
When you write alt text specifically for search engines, you’re creating issues for people with disabilities. That includes folks with temporary or situational disabilities such as slow internet connections.
And if you cram keywords into your descriptions, you’re not really improving your SEO. Ironically, you can improve your search presence much more effectively by following WCAG.
With that in mind, follow these tips when writing alt text:
- Don’t cram in keywords. It’s appropriate to use SEO keywords where they’re relevant. For example, “black t-shirt" might be appropriate for a product image, but “black t-shirt, buy black t-shirt, cool black t-shirt" would be repetitive and frustrating for users.
- Don’t use phrases like “image of" or “picture of" within your alt text. Screen readers will announce images to users, so there’s no need to include that info.
- Describe the image with the first words that come to mind. Imagine that you’re describing your website to a friend over the phone; what words would you use? What information would you include, and what would you omit?
- If an image contains text, include that text in the alt attribute.
For additional tips, read: 5 Steps for Writing Alt Text for Accessibility.
And while alt text isn’t a magic SEO bullet, the best practices of accessibility can certainly help you gain traffic. To learn more, read: 3 Quick SEO Tips (That Also Improve Accessibility).