[{"data":1,"prerenderedAt":30},["ShallowReactive",2],{"blog-body-alt-text-and-captions-en":3},{"content":4,"toc":5},"\u003Cp>Alt text sits at an awkward intersection. It is an accessibility requirement, a fallback for images that fail to load, and a small ranking signal — and the three uses pull in different directions. Write it for a screen reader and it may read as stilted in search results. Write it for a keyword list and it becomes useless to the person who actually needs it.\u003C\u002Fp>\n\n\u003Cp>The conflict is smaller than it looks, because the same underlying discipline satisfies most of both: describe what the image shows, in the context of the page, without repeating what the surrounding text already says. This guide covers that, plus the caption job, which is different and frequently confused with it.\u003C\u002Fp>\n\n\u003Ch2 id=\"two-audiences-one-field\">Two audiences, one field\u003C\u002Fh2>\n\n\u003Cp>The primary audience for alt text is a person using a screen reader, who encounters the image as a sentence inserted into the page's flow. The secondary audience is a person whose image failed to load, and the tertiary one is a search engine building a picture of what the page contains.\u003C\u002Fp>\n\n\u003Cp>Whenever these conflict, serve the first. That is not sentimentality — it is also the method that produces better search outcomes, because writing for a screen reader forces you to state what the image actually contains, while writing for a keyword forces you to state what you want the page to be about. The first produces a description; the second produces a list of nouns.\u003C\u002Fp>\n\n\u003Ch2 id=\"what-alt-text-is-for\">What alt text is for\u003C\u002Fh2>\n\n\u003Cp>Alt text substitutes for an image. If the image were removed and the page had to make the same sense, the alt text is what replaces it. That single principle settles most questions, including the difficult ones.\u003C\u002Fp>\n\n\u003Cp>It also explains why alt text is not a caption, not a title, and not a place for a general remark about the topic. A caption adds information about the image; alt text stands in for it. A chart whose purpose is to show that one series grew faster than another needs alt text conveying that conclusion, not a description of the colours used.\u003C\u002Fp>\n\n\u003Cp>Length follows the same logic. Alt text should be about as long as the sentence you would use to tell someone what the image shows. One clause to one sentence, typically. There is no benefit in going longer, and going shorter usually means information is missing.\u003C\u002Fp>\n\n\u003Ch2 id=\"writing-alt-text-well\">Writing alt text well\u003C\u002Fh2>\n\n\u003Cp>Start with the subject and the action, then add only the details that matter for this page. \"A woman working at a laptop\" is thin; \"A content manager comparing two drafts side by side on a laptop\" tells the reader what the image contributes.\u003C\u002Fp>\n\n\u003Cp>Do not open with \"image of\" or \"picture of\" — screen readers already announce the presence of an image, so those words consume attention without adding information. The one exception worth making is when the format itself carries meaning, as in \"Screenshot of the export dialog showing the CSV option.\"\u003C\u002Fp>\n\n\u003Cp>Keep the wording in the page's language even if the image contains text in another language, and skip keywords that are not visibly present. Alt text that describes something the image does not show is worse than no alt text, because it creates a false impression for someone who cannot check.\u003C\u002Fp>\n\n\u003Ch2 id=\"decorative-images\">Decorative images\u003C\u002Fh2>\n\n\u003Cp>An image that carries no information — a divider, a background texture, an icon sitting next to a label that already says the same thing — should have empty alt text rather than a description. Empty means the screen reader skips it, which is the correct behaviour. Describing decoration inserts noise into every visit.\u003C\u002Fp>\n\n\u003Cp>The distinction is whether removing the image loses information. Removing a divider loses nothing; removing a chart loses the data. Apply that test rather than the aesthetic one, and mark the decorative images deliberately rather than leaving the attribute off, because a missing attribute and an empty one are handled differently by some assistive technologies.\u003C\u002Fp>\n\n\u003Ch2 id=\"captions-are-a-different-job\">Captions are a different job\u003C\u002Fh2>\n\n\u003Cp>A caption is visible to everyone and its job is to make the image worth looking at. Where alt text stands in for the image, a caption adds to it: context, a consequence, a number that makes the point concrete.\u003C\u002Fp>\n\n\u003Cp>Good captions are short, and the best ones say something the surrounding prose does not. A caption that restates the paragraph above the image is decoration; a caption that says what the reader should notice — \"The second draft is 40% shorter with no loss of detail\" — earns its place.\u003C\u002Fp>\n\n\u003Cp>Captions are also read more than body text on most pages, because they sit next to a visual anchor and are easy to scan. That makes them a legitimate place for the one specific detail you could not fit into the prose, and a bad place for filler you wrote because the field existed.\u003C\u002Fp>\n\n\u003Ch2 id=\"filenames-matter-less-than-people-think\">Filenames matter less than people think\u003C\u002Fh2>\n\n\u003Cp>Descriptive filenames are worth having, mostly as an organisational convenience for humans. They are a weak signal, and rewriting three hundred filenames to insert keywords is a poor use of a month.\u003C\u002Fp>\n\n\u003Cp>What does matter is that filenames and alt text are not copies of each other, and that you do not end up with fifty images called the same thing. If you have a naming convention, apply it to new uploads and stop there. Format and compression matter more than the name, and image search traffic arrives through the page it sits on, not through the file.\u003C\u002Fp>\n\n\u003Ch2 id=\"auditing-an-existing-image-set\">Auditing an existing image set\u003C\u002Fh2>\n\n\u003Cp>Sort your images by the pages they appear on and start with the pages that already get traffic. Images on pages nobody visits can wait indefinitely.\u003C\u002Fp>\n\n\u003Cp>Group them into three buckets: images with no alt attribute, images whose alt text is a filename or keyword string, and images with reasonable alt text. Fix the first two buckets on high-traffic pages and ignore the rest. For the third bucket, check one thing: whether the alt text describes the image or something adjacent to it. A surprising number of \"good\" alt texts describe the article's topic rather than the picture.\u003C\u002Fp>\n\n\u003Cp>Do not run a bulk tool that generates alt text for every image on the site without review. It produces fluent descriptions of things that are not in the images, and it does so at a scale that makes the review impossible. Reviewing one page at a time is slower and correct.\u003C\u002Fp>\n\n\u003Ch2 id=\"where-to-spend-your-time\">Where to spend your time\u003C\u002Fh2>\n\n\u003Cp>If you have an hour, spend it like this. First, the images on your five most-visited pages, written properly. Second, empty alt attributes on decorative images, so screen readers stop announcing them. Third, captions on the three images that carry the most argument in your best article.\u003C\u002Fp>\n\n\u003Cp>What you should not do is treat alt text as a keyword surface, or treat the whole thing as a project with a finish date. It is a thirty-second habit each time you upload an image, and the sites that do it well are the ones where nobody ever launched an initiative about it.\u003C\u002Fp>",[6,9,12,15,18,21,24,27],{"id":7,"text":8},"two-audiences-one-field","Two audiences, one field",{"id":10,"text":11},"what-alt-text-is-for","What alt text is for",{"id":13,"text":14},"writing-alt-text-well","Writing alt text well",{"id":16,"text":17},"decorative-images","Decorative images",{"id":19,"text":20},"captions-are-a-different-job","Captions are a different job",{"id":22,"text":23},"filenames-matter-less-than-people-think","Filenames matter less than people think",{"id":25,"text":26},"auditing-an-existing-image-set","Auditing an existing image set",{"id":28,"text":29},"where-to-spend-your-time","Where to spend your time",1791511468521]