ALT text, or alternative text, is a concise written description linked to an image’s HTML tag that clarifies what the image represents. It fulfills two essential functions:
ALT text, or alternative text, is a concise written description linked to an image’s HTML tag that clarifies what the image represents. It fulfills two essential functions:
- Accessibility – It enables screen readers to convey the image’s details to users with visual impairments.
- SEO – This assists search engines in grasping the content of the image, enhancing its indexing and relevance for search inquiries.
For example:
<img src=”image.jpg” alt=”Young woman working on laptop in a cozy coffee shop”>
Why ALT Text Matters for SEO
- Enhances Image SEO: Search engines are unable to interpret images directly; they depend on ALT text for understanding.
- Boosts Page Relevance: Well-labeled images enhance the content’s context, aiding in semantic search.
- Contributes to Ranking Factors: Although it may not be the most significant element, ALT text contributes to user experience and signals of page relevance.
- Improves Accessibility Compliance: Websites that utilize appropriate ALT text comply with ADA and WCAG standards, highlighting their significance for both ethical and legal considerations.
Best Practices for Writing ALT Text
| Good Practice | Why It Matters |
| Describe the image clearly | So users and crawlers understand the image’s purpose |
| Keep it concise (under 125 characters) | Screen readers typically cut off long descriptions |
| Include relevant keywords naturally | Helps with contextual ranking without keyword stuffing |
| Avoid using “image of” or “picture of” | Redundant and unnecessary |
| Leave ALT empty if the image is decorative | For accessibility, this prevents noise for screen readers |
Bad vs. Good Examples
Bad ALT Text:
img alt=”image123.jpg”>
<img alt=”click here”>
<img alt=”SEO”>
Good ALT Text:
<img alt=”Team of digital marketers analyzing campaign performance charts”>
<img alt=”Boston skyline during golden hour with SEO Agency Boston billboard”>
HTML Format of ALT Text
- HTML
- CopyEdit
- <img src=”seo-report.jpg” alt=”SEO expert analyzing keyword report on a laptop screen”>
Note: ALT text is placed directly inside the img tag using the alt=”” attribute.
ALT Text vs. Other Image Attributes
| Attribute | Purpose | Used For |
| alt | Accessibility + SEO | Screen readers, Google image indexing |
| title | Tooltip when hovering | UX enhancement |
| filename | Minor SEO signal | Image file relevance (e.g., seo-report.jpg) |
| Caption | Text shown below the image | Visual context for all users |
Common Use Cases
- Blog thumbnails
- Product images on e-commerce sites
- Infographics and charts
- Service diagrams or illustrations
- Background visuals that convey information
ALT Text & Google’s Guidance
“When selecting alt text, prioritize crafting valuable, informative content that incorporates relevant terms effectively and aligns with the overall context of the page.”— Google Images Best Practices
Related Terms
- Image SEO
- Structured Data
- Accessibility SEO
- Core Web Vitals
FAQs About ALT Text
No — purely decorative images should have empty ALT attributes (alt=””).
Absolutely, of course. Steer clear of overusing keywords or including unrelated expressions.
No — unless the image doesn’t appear. ALT is mainly accessed through screen readers or viewed in the HTML of the page.
Make Every Image Count
Outstanding content calls for impressive visuals — and those visuals require well-crafted ALT text. At SEO Agency Boston, we create user-friendly, SEO-optimized websites where each image serves a meaningful role and conveys a message.
Need an Image SEO Audit? Let’s Talk.
