The clear explanation
Alt Text, in plain English.
Alt text, short for alternative text, is a small snippet of text added to an image's HTML tag that explains what the image shows or its role on the page. For a small business, it’s a practical accessibility feature and a lightweight way to give search systems extra context about your visuals. Useful alt text is concise, accurate, and focused on the image's purpose, think product identifiers, key attributes, or the action shown. Decorative images can use an empty alt attribute so assistive technology skips them. Adding or improving alt text only takes a few minutes per image but makes your site easier to use for customers who rely on screen readers and gives your content clearer signals for search and indexing tools.
Useful alt text makes important visual information available to more visitors and gives search systems better context about the page.
What to remember
- Alt text is the img tag's short description that helps screen readers explain visuals and gives search systems additional context; it's a simple accessibility and content-signaling practice.
- Write concise, specific alt text focused on the image's purpose: product name and key details for photos, action for instructional images, and transcription for on-image text.
- Use alt="" for purely decorative images so assistive tech skips them, and provide extended descriptions via captions, aria-describedby, or linked pages for complex visuals.
- Add alt text through your CMS or developer workflow, prioritize meaningful images first, and update older content to improve accessibility and clarity with little time investment.
01 / Learn the concept
How alt text works in HTML and assistive technology
Alt text is stored in the img tag's alt attribute, for example alt="description". Screen readers announce that text when an image conveys information, and browsers display it if the image fails to load. Search engines also read alt attributes as one of several signals to interpret an image's subject and relevance, alongside captions, surrounding copy, file names, and structured data. Most content management systems provide a field for alt text when you upload images, and developers can add it directly in the HTML. Make sure meaningful images have an alt attribute and avoid leaving important images untagged.
02 / Learn the concept
Writing alt text that helps customers and search systems
Good alt text is clear and purposeful. For product photos, include the product name and a distinguishing detail, such as color or size. For how-to images, describe the action and why it matters to the user. If text appears in the image and matters, transcribe it. Avoid phrases like "image of" because screen readers already announce an image. Aim for brevity, roughly a short sentence or about 125 characters when practical, but always favor meaning over strict length limits. The guiding question: what would a customer need to know if they couldn't see this image?
03 / Learn the concept
When to use empty alt, captions, or extended descriptions
Not every image needs a descriptive alt attribute. Purely decorative images should use an empty alt attribute alt="" so assistive tech skips them. Complex visuals, like charts, infographics, or maps, often need a short alt summary plus a linked or nearby extended description (in a caption, aria-describedby, or separate page). For e-commerce, provide concise alt text for product images and place specifications, measurements, and detailed info in accessible text elsewhere. Choosing the right approach keeps assistive readers focused on useful content without overloading them.
Practical example
Alt Text in a practical scenario
Consider this hypothetical:
Instead of leaving an image file named "IMG_1234.jpg" on their homepage, a landscaping company adds text reading "Stone patio with outdoor kitchen built in Seattle." This tells search engines exactly what the image shows and helps visually impaired visitors understand the photo.
Avoid the expensive shortcuts
Common mistakes and misconceptions.
Leaving alt blank for meaningful images
Omitting alt attributes or leaving them empty for product or instructional images prevents screen reader users from accessing important information. It also removes a useful context signal for search systems. Add descriptive alt text when an image conveys information or supports calls to action.
Keyword stuffing or spammy descriptions
Using alt text as an SEO dumping ground, repeating keywords or adding unrelated phrases, produces low-value descriptions for users and can harm perceived relevance. Alt text should accurately describe the image for people first, with natural wording.
Over-describing decorative images
Providing long, literal descriptions for decorative images creates unnecessary noise for screen reader users. If an image adds no informational value, use an empty alt attribute so assistive tech ignores it and focus descriptive effort where it matters.
Put the idea to work
What a business owner can do next.
- 01
Audit your site for missing or empty alt attributes
Run a site audit using your CMS, browser accessibility extensions, or automated tools to list images missing alt text. Start with product and service photos, then build a prioritized spreadsheet and assign someone to add concise, accurate alt text.
- 02
Write clear, purpose-focused alt text
For each meaningful image, write a short sentence stating what the image shows and why it matters on the page. Include essential details like product name, color, or action, and avoid phrases like "image of."
- 03
Use empty alt for decorative images
Mark purely decorative images with alt="" so screen readers skip them. Confirm the image truly adds no informational value before doing this. Decorative SVGs or backgrounds often belong in CSS rather than HTML for clearer semantics.
- 04
Document standards and train staff
Create a short internal guideline with examples for alt text, including when to use empty alt, how to transcribe on-image text, and when to add extended descriptions. Train content editors and freelancers to apply these standards consistently.
Common questions
What owners usually ask about Alt Text.
How long should alt text be?
Aim for concise descriptions, typically under about 125 characters or a short sentence, because some assistive tools truncate lengthy strings. That said, meaning matters more than length. For complex visuals, use a brief alt and provide an extended description nearby or linked so users can access full details.
Can alt text improve SEO?
Alt text helps search engines understand an image's subject and role on the page, so it can contribute to relevance signals for image search and page context. It is one of many factors, alongside captions, surrounding copy, file names, and structured data. Focus on accurate, user-first descriptions rather than keyword stuffing.
What should I do with decorative images and icons?
If an image or icon is purely decorative, use an empty alt attribute alt="" so assistive technology ignores it. For icons that convey meaning, include concise alt text like "search" or "close." If an icon is implemented as a CSS background, ensure its function is described in nearby accessible text.
Authoritative further reading
Use these primary and authoritative resources when you need deeper technical or platform-specific guidance.