Writing Alt Text That Boosts SEO (Without Keyword Stuffing)

Alt text is one of the most misunderstood elements in SEO. Some people ignore it entirely. Others stuff it with keywords until it's unreadable. The truth is simpler: write alt text for humans, and search engines will reward you. Here's how.

What Is Alt Text?

Alt text (alternative text) is a written description of an image. It appears:

• When images fail to load
• When read by screen readers for visually impaired users
• When indexed by search engines

<img src="cover-image.jpg" alt="Writer typing on laptop in coffee shop">

The alt attribute tells everyone—humans and bots—what the image shows.

Why Alt Text Matters

Accessibility

Over 2 billion people globally have visual impairments. Screen readers convert alt text to speech, making your content accessible to them.

Without alt text: "Image" With alt text: "Writer typing on laptop in coffee shop"

The difference is the difference between inclusion and exclusion.

SEO

Search engines can't "see" images. They rely on alt text to understand image content. Good alt text helps:

• Images appear in Google Image Search
• Pages rank for relevant queries
• Content gets properly indexed
• Rich snippets display correctly

User Experience

When images don't load (slow connections, broken links, email clients blocking images), alt text tells users what they're missing.

The Alt Text Formula

Good alt text follows a simple pattern:

[Subject] + [Action/Context] + [Relevant Detail]

Examples:

Keep it:

• Descriptive: What does the image actually show?
• Concise: Under 125 characters when possible
• Contextual: Relevant to the surrounding content

What NOT to Do

Don't Stuff Keywords

❌ "Best cover image blog cover image free cover images download cover image"

This hurts both accessibility and SEO. Screen readers will read this gibberish aloud. Google recognizes keyword stuffing and may penalize you.

✅ "Colorful abstract background suitable for blog headers"

Don't Start with "Image of" or "Picture of"

❌ "Image of a sunset over mountains"

Screen readers already announce "image" before reading alt text. This creates redundancy: "Image: Image of a sunset..."

✅ "Sunset over Rocky Mountains with orange and purple sky"

Don't Leave It Empty (Usually)

❌ alt=""

Empty alt text tells screen readers to skip the image entirely. Only use this for purely decorative images that add no meaning.

✅ alt="Dashboard showing weekly analytics overview"

Don't Describe Irrelevant Details

❌ "Photo taken with Canon EOS 5D at f/2.8, 1/200s, ISO 400, showing a person"

Users don't care about camera settings. Describe what matters.

✅ "Photographer adjusting camera settings outdoors"

Don't Use the Filename

❌ alt="IMG_4523.jpg" or alt="header-image-final-v2"

This tells users nothing. Always write descriptive text.

Alt Text by Image Type

Different images need different approaches:

Photographs

Describe the subject, action, and relevant context.

• "Chef preparing pasta in restaurant kitchen"
• "Team meeting in modern glass conference room"
• "Child reading book under tree in park"

Screenshots

Describe what the screenshot shows and why it matters.

• "Google Analytics dashboard showing traffic sources"
• "Error message displaying 404 page not found"
• "Settings panel with notification options highlighted"

Charts and Graphs

Summarize the key data or trend.

• "Line graph showing revenue growth from $1M to $3M over 2025"
• "Pie chart with email at 45%, social at 30%, organic at 25%"
• "Bar chart comparing pricing across three competitors"

For complex data, consider adding a text description below the image too.

Logos

Include the company/brand name.

• "Stripe logo"
• "Microsoft Azure logo on blue background"
• "CoverImage.app logo"

Decorative Images

If an image is purely decorative (adds no information), use empty alt text:

<img src="decorative-border.png" alt="">

This tells screen readers to skip it. Use sparingly—most images add some value.

Icons

For icons, describe their function, not their appearance.

• ❌ "Three horizontal lines"

• ✅ "Menu"

• ❌ "Magnifying glass"

• ✅ "Search"

Cover Images

For blog cover images, describe what the image shows and how it relates to the content.

• "Person organizing tasks on whiteboard for productivity article"
• "Close-up of coffee being poured for morning routine post"
• "Abstract geometric pattern in brand colors"

SEO Best Practices

Include Relevant Keywords Naturally

If your article is about "remote work productivity," and your image shows someone working from home:

✅ "Woman working on laptop at home office desk"

The keyword context is natural. Don't force it.

Match Image to Content

Alt text should reflect what's on the page. If your article is about JavaScript and your image shows generic coding:

• ❌ "Person coding" (too vague)
• ✅ "Developer debugging JavaScript in VS Code" (specific, relevant)

Be Specific

Specific alt text ranks better than generic:

• ❌ "Food on plate"
• ✅ "Grilled salmon with asparagus and lemon on white plate"

Specific descriptions match more long-tail searches.

Consider Image Search

People search Google Images. Good alt text helps your images appear for relevant queries.

If you want traffic from "minimalist home office setup," your image alt text should describe exactly that.

Alt Text Length

The 125-Character Guideline

Screen readers traditionally cut off alt text around 125 characters. While modern readers handle longer text, brevity is still good practice.

Short and clear beats long and detailed:

• ❌ "A professional business woman in her mid-thirties wearing a blue blazer is sitting at a wooden desk in a bright, modern office space with large windows, typing on a silver laptop while looking at spreadsheets displayed on the screen" (261 characters)

• ✅ "Business professional analyzing spreadsheets on laptop in modern office" (71 characters)

When to Go Longer

Complex images (infographics, detailed charts) may need more description. Options:

1. Longer alt text (acceptable)
2. Brief alt + detailed caption
3. Brief alt + linked full description

For infographics, consider a text version of the key points below the image.

Platform-Specific Tips

WordPress

• Fill in the "Alt Text" field when uploading
• Edit existing images in Media Library
• Consider SEO plugins that flag missing alt text

Ghost

• Click on image, add alt text in sidebar
• Alt text transfers to social sharing

Medium

• Click image, select "Alt text" option
• Limited to 500 characters

Dev.to / Hashnode

• Use markdown: ![Alt text here](image-url.jpg)
• Keep it concise

Social Media

Each platform handles alt text differently:

Testing Your Alt Text

Screen Reader Test

Use a screen reader to hear your alt text:

• Mac: VoiceOver (Cmd + F5)
• Windows: Narrator (Win + Ctrl + Enter) or NVDA (free)
• Chrome: Screen Reader extension

Listen to your page. Does the alt text make sense without seeing the image?

The Phone Test

Read your alt text out loud as if describing the image to someone over the phone. If it sounds awkward or unhelpful, rewrite it.

Automated Tools

• WAVE: Browser extension that flags missing alt text
• Lighthouse: Chrome DevTools accessibility audit
• axe: Comprehensive accessibility testing

Common Questions

Q: Should every image have alt text?

Almost every. The only exception is purely decorative images (borders, spacers, background textures). Use alt="" for those.

Q: How do I write alt text for complex infographics?

Provide a brief description in alt text, then include a text summary below the image or link to a detailed description.

Q: Does alt text help with page ranking or just image ranking?

Both. Good alt text helps search engines understand your page content, contributing to overall relevance signals.

Q: Should I include my brand name in alt text?

Only if the image actually shows your brand (logo, product). Don't add brand names to unrelated stock photos.

Q: What about background images in CSS?

CSS background images can't have alt text. If the image conveys meaning, use an <img> tag instead, or add a visually hidden text description.

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Don't Forget the Alt Text

Finding the perfect cover image is just the first step. Add descriptive alt text to improve accessibility, boost SEO, and help your content reach more people. CoverImage.app reminds you to add alt text when you download—because great images deserve great descriptions.