Glossary | 3 mins
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Alt text refers to a written description of an image on a web page, attached to that image as an HTML element. This HTML element was originally conceived in the early history of the internet, when some browsers were strictly text based. These days however, it’s simply used to help users visualise an image if they can’t see it in detail for any reason, for example if they’re visually impaired.
What Does Alt Mean?
The “alt” in “alt text” is a contraction of “alternative”. Alt text is so labelled because the text is intended to act as an alternative to seeing the image.
Why Does Alt Text Matter?
SEO professionals need to consider how they use alt text for two key reasons.
Firstly, using alt text will improve the user experience and accessibility of a site, and allow site visitors to access all the image content on a page, even if they’re blind or visually impaired. It can also be helpful for web users who have certain learning disabilities or conditions that affect their sensory processing. Alt text can also make a site more accessible in rare cases where a page doesn’t load properly or a site user has opted not to view images.
The second reason to think about alt text in an SEO context is that the descriptions you use in them can provide important semantic cues that search engines use to rank images in search results. The more accurate and helpful your alt text is, the easier it will be for Google to understand and rank your content.
Alt Text Best Practices
With each piece of alt text you write, the most important thing is to keep it succinct and specific.
Some screen reading tools have a character limit for every instance of alt text they read, so make sure that you’re keeping within 125 characters to avoid them stopping short. The vast majority of alt text fields can be filled effectively with just a few words, though complex images (e.g. graphs with detailed legends) could require a more detailed sentence.
Though it’s good practice to keep alt text short, it’s also important to be descriptive and specific about what the image contains. For example, if you were describing an image from a football match, the alt text should name the players in frame and the league or tournament the match is a part of, and not something vague like “footballer kicking ball”.
When writing alt text for images, one of the easiest ways to stay on the right track is to imagine you’re describing the image in front of you over the phone, and trying to give the person you’re speaking to an accurate idea of it in as few words as possible.
Alt Text FAQs
How to write alt text?
The way you write alt text and assign it to images will vary from one CMS to another, but the alt text field can generally be found alongside other image settings like dimensions, captions, and borders.
In the WordPress editor, for example, clicking on an image will open its block tab. Scroll down to “Image settings”, and you’ll see a text field labelled |”Alt text (alternative text)”. Simply enter your desired alt text, click “Update”, and the alt text will be assigned to the image.
How do I find alt text on a website?
You can check alt text on a website by right-clicking on an image and clicking “Inspect” (“Inspect Element” on Edge.) This will bring up a sidebar displaying the page’s HTML code with a highlight over the image you’ve clicked on. Find the element “alt=” – this will be followed by the alt text.
You can also check alt text by enabling a screen reader on your browser and clicking the image. This can be helpful if you’d like to know exactly how your alt text will sound to people with visual impairments when browsing the page.
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