Alt Text for Blog Images: A Practical Writing Guide and Accessibility Checklist

Overview

Alt text, short for alternative text, is a written description attached to an image in a webpage. Assistive technologies may read it aloud, and browsers may display it when an image is unavailable. More importantly, alt text communicates the image's role in the article: what information it adds, what action it supports, or whether it is purely decorative.

Good alt text is not a caption, file name, keyword list, or full transcript of every visible detail. It is a concise substitute for the image's meaning in context. The same image can need different alt text in different articles because its purpose changes.

For example, a photograph of a notebook might need alt text such as Open notebook beside a laptop on a wooden desk in a post about writing routines. In a post about a specific product, the useful description might identify the product and its relevant feature instead.

Alt text is one part of a broader SEO content refresh system. It should support the page's topic and structure, but it should never be forced to repeat a target keyword. Search visibility is a possible benefit of clear image context; accessibility is the primary reason to write it.

What to track

1. The image's purpose

Before describing an image, ask what a reader loses if it is hidden. The answer determines the type of alt text you need.

• Informational image: Describe the important subject, action, or result.
• Functional image: Describe the action or destination when the image is a link or control.
• Screenshot: Explain the interface, setting, and step the reader needs to understand.
• Chart or diagram: Summarize the main relationship or conclusion, and provide detailed data elsewhere when necessary.
• Decorative image: Use empty alt text when the image adds visual atmosphere but no information.

2. The surrounding text

Read the heading, paragraph, caption, and nearby links before writing. Do not repeat information that the surrounding text already communicates unless the image needs that information to make sense. A caption can provide context while alt text explains the image's essential content.

3. Specific details that matter

Include details only when they help readers understand the article. Relevant details may include a person's action, an object's distinguishing feature, a visible label, a chart's direction of change, or the state of a user interface. Avoid guessing identities, emotions, locations, or technical details that are not established by the image or article.

4. Length and clarity

There is no single ideal length for every image. Aim for the shortest description that preserves the image's purpose. Start with the subject and use ordinary language. Remove phrases such as image of or picture of when the context already identifies the content as an image. Avoid keyword stuffing, decorative adjectives, and unnecessary visual inventory.

Alt text examples by image type

• Product screenshot: Analytics dashboard showing monthly page views and traffic sources.
• Instructional screenshot: Image settings panel with the alternative text field selected.
• Chart: Bar chart comparing four traffic sources, with search contributing the largest share.
• Portrait used for identification: Editor Maya Chen speaking at a desk during a recorded interview.
• Decorative divider: Use empty alt text if the divider has no informational role.
• Linked logo: Describe the link destination or organization, such as Readers Life home page, rather than simply logo.

For a complex chart, do not try to compress every value into one sentence. Use a nearby table, written summary, or expandable description for the complete data. The alt text can state the chart type and main takeaway while directing readers to the detailed information.

A reusable alt-text template

Use this structure as a starting point: [subject or image type] + [important action, relationship, or feature] + [context needed to understand its role]. For example: Line chart showing email sign-ups increasing after a new content upgrade was added to the article. Edit the template rather than applying it mechanically. If the image is decorative, the correct choice may be an empty alt attribute rather than a description.

Cadence and checkpoints

Make alt-text review part of the publishing workflow instead of treating it as a final technical task. A simple checkpoint sequence works for most blog posts.

1. During drafting: Decide why each planned image belongs in the article. If you cannot explain its purpose, reconsider using it.
2. During image insertion: Write alt text while the image's context is fresh. Check whether the CMS has separate fields for alt text, caption, title, and description; use the field intended for accessibility.
3. Before publishing: Review the rendered page, not only the editor view. Confirm that meaningful images have useful descriptions, decorative images are not announced unnecessarily, and linked images communicate their destination.
4. Monthly or quarterly: Sample older posts, especially high-traffic evergreen pages and articles with many screenshots. Check whether images, interfaces, examples, or surrounding claims have changed.
5. After a redesign or CMS change: Recheck a representative set of pages. Platform settings and image fields can change, so confirm that existing alt text remains attached and editable.

Keep a lightweight accessibility tracker with the page URL, image location, image purpose, current alt text, reviewer, and next review date. This is more useful than trying to audit every image repeatedly without recording what changed.

How to interpret changes

When reviewing alt text, look for meaning rather than a particular word count or score. A description may need revision if a reader who cannot see the image would miss an instruction, comparison, identity, or conclusion.

If a screenshot no longer matches the interface, update the screenshot, its alt text, and the surrounding instructions together. Changing only the description can leave the article confusing.

If a chart's conclusion has changed, revise the alt text and the written interpretation. Do not preserve an old summary simply because the image file name has stayed the same.

If an image is repeated across several pages, review it in context. A generic description may work in one article but be incomplete in another. If the image is a link, check that the description makes the destination or action clear.

If alt text contains a string of keywords, rewrite it as a natural description. The goal is to convey meaning, not to create an additional place to insert search terms. For related on-page improvements, see this guide to improving blog readability.

If an image adds no information, consider whether it should be marked decorative or removed. A long description for a purely decorative flourish can create unnecessary noise for people using assistive technology.

AI tools can suggest a first draft, but a human editor should verify the subject, context, labels, and purpose. An automated description may identify visible objects while missing the point the image makes in the article. Use the same fact-checking discipline described in an AI-assisted editing workflow.

When to revisit

Review alt text whenever you publish a new post, replace an image, change a screenshot, update a chart, or alter the paragraph that explains an image. For an evergreen blog, schedule a focused review monthly or quarterly, depending on how frequently the site changes. Prioritize pages that receive consistent traffic, support important reader tasks, or contain time-sensitive interfaces and data.

Use this pre-publish checklist:

• Does every meaningful image have alt text that explains its role?
• Does each description match the surrounding article rather than merely listing visible objects?
• Are screenshots current and understandable without relying on color alone?
• Do charts include their main takeaway, with detailed data available in text when needed?
• Are decorative images treated as decorative rather than given distracting descriptions?
• Do linked images explain the action or destination?
• Have unnecessary phrases, guesses, and keyword repetitions been removed?
• Was the page reviewed in its rendered form after publishing?

Set the next review date when you finish the current one. That small habit turns alt text from a one-time upload field into part of a maintainable SEO and accessibility workflow. For each new image, identify its purpose first, write the shortest accurate description, and check it again when the page or image changes.