Synonyms: Alternative text Alt attribute Image description
An Alt tag (short for alternative text) is a written description that can be added to the HTML code of an image on a webpage. The primary purpose of an Alt tag is to describe the content and function of an image to users who may not be able to view it, such as visually impaired individuals using screen readers or when the image fails to load. It also plays an important role in SEO by helping search engines understand the image’s content.
Why Are Alt Tags Important?
Alt tags serve multiple key purposes:
1. Accessibility
Alt tags make the web more accessible by allowing visually impaired users to understand what an image represents through screen readers. The screen reader reads out the Alt tag description, providing an alternative way for users to interact with the content.
2. SEO
Search engines can’t “see” images the way humans do. Instead, they rely on Alt tags to understand the image’s content and context. Including relevant keywords in your Alt tag can improve your page’s SEO, helping your images and pages rank higher in image search results.
3. Image Load Issues
If an image fails to load due to slow internet connections or technical issues, the Alt tag text will display in place of the image, giving users an idea of what was intended to appear.
How to Write a Good Alt Tag
A well-crafted Alt tag should be:
- Descriptive: Clearly describe the image. For example, instead of writing “dog,” you might write “brown dog running in the park.”
- Concise: Keep it brief, ideally under 125 characters, so it’s easy for screen readers to process.
- Keyword-rich: If it fits naturally, include keywords relevant to the page’s content for SEO benefits. However, avoid keyword stuffing, as this can negatively affect both user experience and SEO.
Example of a Good Alt Tag:
For an image of a person baking cookies, a good Alt tag could be:
<img src="cookies.jpg" alt="Person baking chocolate chip cookies in a kitchen">This Alt tag is specific, relevant to the content, and gives context to both search engines and users.
Common Mistakes to Avoid
- Overstuffing keywords: Adding too many irrelevant keywords can harm your SEO.
- Vague descriptions: Tags like “image123.jpg” or “picture” don’t provide any meaningful information.
- Leaving the Alt tag blank: Unless the image is purely decorative (in which case, an empty Alt tag is acceptable), always include an Alt tag.