Alt text (or ‘alternative text’) might seem like a small, additionally time-consuming detail, but it carries enormous weight in both accessibility and SEO. It’s what screen readers use to describe images for visually impaired users, and it’s also what search engines read to understand what an image represents.

For marketing managers, writing effective alt text is not just important because of compliance. It’s important because it ensures that every image communicates clearly to all audiences. Done well, it not only improves your website’s accessibility, but your search visibility, and even click-through rates on image search.

In this short guide, the KIJO team – a website design company in London – we’ll break down exactly how to write alt text that’s clear, inclusive, and optimised.

What Is Alt Text?

Alt text is a short written description of an image that appears in the HTML code. The code looks like this:

<img src=”your-image.jpg” alt=”Your Alt Text Here” />

 Its purpose is to explain the content and function of an image when it can’t be seen.

For example:

• “Woman Laptop” – This is an unhelpful description.
  
• “Two women reviewing a digital marketing campaign on a laptop” – This description is clear, succinct and relevant.

When it comes to writing alt text, think of it as another opportunity to use your brand’s voice when images can’t speak for themselves.

WCAG Alt Text: Meeting Accessibility Standards

The Web Content Accessibility Guidelines (WCAG) set the global standards for digital accessibility, and alt text is one of their key principles.

According to WCAG 2.2, every non-decorative image must have equivalent text alternatives. That means your alt text should:

• Convey the same meaning or function as the image.
  
• Be concise. You want to aim for under 125 characters where possible.
  
• Avoid redundancy (no need to say “Image of…”).
  
• If there’s an image being used as a decorative object or an image that’s indicative of an action, it won’t need alt text. Instead, it will need an ARIA tag adding to it to describe what it is. The ARIA tag means it will indicate what the image is, ie. “Left Arrow”, or “Telephone Icon” instead of descriptive text. These are processed and presented slightly differently on screen readers which are used by visually impaired users. You can learn how to apply an ARIA tag here.

For marketing managers, following WCAG is about honouring your brand’s responsibility. Inclusive design, including the use of alt text, communicates that your company values every visitor.

How to Write Alt Text

Alt text should describe the content and purpose of an image. A good rule of thumb? Imagine describing the image over the phone to someone who can’t see it.

1. Describe what’s important
   Focus on the context, not every detail. (No, we don’t need to know if someone’s wearing a V-neck jumper or a scoop neck.)
   
2. Add its function
   If it’s a button or link, include what it does (e.g., “Download our 2025 Health Report”).
   
3. Keep it short
   Aim for around eight to twelve words where possible
   
4. Include keywords naturally
   Like you would in general copy, only include keywords when relevant, and don’t force them in. 

Using these pointers, a good example of alt text would therefore be: “Woman typing on laptop to schedule a social media post in Hootsuite.”

And, a bad example of alt text would be: “Laptop, coffee cup, office desk, woman, marketing, digital, alt text, SEO.”

How to Write Alt Text on Instagram

If you also manage social media accounts and market on them, it’s worth noting that Instagram now allows custom alt text on posts too. This is both an easy win for accessibility, reach, and brand reputation.

To add alt text on Instagram, simply:

1. Upload your photo.
   
2. Before posting, tap ‘Advanced Settings’.
   
3. Under ‘Accessibility’, tap ‘Write Alt Text’.
   
4. Add a short, descriptive sentence!

Example:
“Flat lay of skincare products in pastel packaging on a marble counter.”

Alt text on Instagram not only supports users with screen readers, but it can also help your posts rank in image search. This, in turn, promotes discoverability for your brand!

How to Write Alt Text for Infographics

Infographics can be tricky because they often include a lot of embedded text. Here’s a suggestion on how to handle them:

• Provide a brief summary in the alt text (e.g., “Infographic comparing organic vs paid traffic growth in 2024”).
  
• Then, try to include the full data or text in the body copy or a nearby caption for complete accessibility.

If your infographic is interactive or animated, try to add a detailed text version on the page or in an accompanying article if possible.

How to Write Alt Text for Tables, Graphs, and Chart Images

Images of tables, charts or graphs are another tricky thing to get right in terms of accessibility. For simple graphics, alt text can describe the purpose:

“Table showing monthly website traffic growth across four campaigns.”

For complex tables, graphs or charts (e.g., data-heavy financials), provide a caption or summary paragraph instead of relying solely on alt text. This helps users understand the data trends, not just cell-by-cell content.

How to Write Alt Text for Screenshots

Screenshots should always explain the relevant action or outcome. A good example would be: “Screenshot of the Google Analytics dashboard showing a 25% rise in organic traffic.”

A bad example would be: “Screenshot of a computer screen with graphs and numbers.”

If the screenshot shows sensitive or private data, consider blurring those areas or providing a written summary instead.

How to View Alt Text

Need to check if your website images have alt text? You can:

• Right-click on the image. Then, select ‘Inspect’ and look for ‘alt=”…”’ in the code.
  
• In CMS platforms like WordPress, you can check your media library or image block settings.

On social media, most platforms (like Instagram, as mentioned above) allow you to add or edit alt text manually before posting.

When (and When Not) to Include Ethnicity, Gender, or Additional Characteristics in Alt Text

You should mention a person’s ethnicity, gender, age, or physical characteristics only when those details are directly relevant to the purpose of the article or page, or meaning of the image.

Examples where you should include it:

• A healthcare article discussing diversity in clinical research:
  
  “Black female doctor administering a vaccine to a young, Asian patient.”
  
  
• A news story or report where representation is part of the narrative:
  
  “A group of women from different ethnic backgrounds at a business networking event.”

In these cases, those traits convey important context about inclusion, demographics, or representation.

If your brand wants to express inclusivity through imagery, you absolutely can (and should) reflect that in your alt text. But, the key is always intent and context! If an image is designed to show diversity, then describing that diversity adds value for users relying on screen readers. It goes without saying – always avoid performative inclusion.

It goes without saying – always avoid performative inclusion. If ethnicity or gender isn’t meaningful to the content – for example, a generic business, education, or lifestyle shot – you don’t need to mention it.

Examples where you shouldn’t include it:

• “Man presenting data in a meeting” is enough – no need to specify race or age.
  
• “Customer browsing online shop on a laptop” works without identifying gender.

Adding unnecessary identity markers can feel tokenistic, especially if assumptions are made about someone’s background based purely on appearance.

When in doubt, ask yourself:

“If I were describing this aloud to someone over the phone, would mentioning gender or ethnicity help them understand the purpose of the image?”

If the answer is no, you can probably leave it out.

Final Thoughts on Writing Alt Text

Alt text might feel like small extra to-do and unnecessary after thought, but it’s one of those behind-the-scenes details that actually enhances digital marketing. It supports your brand’s accessibility goals, strengthens your SEO, and ensures your content performs well across all channels, from websites to social media. For marketers, learning how to write alt text well means you’re making sure that every visual counts.

If you’re redesigning your website or auditing your digital accessibility, the KIJO team can help create an image strategy that’s both compliant and conversion-driven – ensuring your visuals speak to everyone. Get in touch today if you think we can help.

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