Nayan Dhumal
Alt text is a short description of an image, added in your page’s code. Screen readers read it aloud to people who cannot see the image, and search engines use it to understand what the image shows. This guide explains how to write good alt text, with examples, and how to add it in WordPress.
Every image on your blog can have alt text. Most beginners leave it empty or fill it with keywords. Both are missed opportunities.
Good alt text takes a few seconds to write once you know what it is for.
Key takeaways
- Alt text describes an image for people who cannot see it and for search engines.
- Google calls it “a short, but descriptive piece of text that explains the relationship between the image and your content.”
- Describe what the image shows in the context of the post.
- Keep it short and specific.
- Do not stuff it with keywords. Google warns this can look like spam.
- Purely decorative images can have empty alt text.
What alt text is
In HTML, an image looks like this: an img tag with an alt attribute. The alt attribute holds the description. Readers do not normally see it on the page. It appears when the image cannot load, and screen readers read it aloud.
Google’s SEO starter guide describes it as “a short, but descriptive piece of text that explains the relationship between the image and your content.”
Why alt text matters
- Accessibility: people using screen readers hear the description instead of nothing.
- Search: Google uses alt text, along with the page content, to understand what an image shows.
- Image search: clear alt text helps your images appear for relevant searches.
- Linked images: when an image is a link, Google treats its alt text like anchor text.
Good and bad alt text
Google’s own documentation uses a simple example of a puppy photo. Here is the same idea applied to a blog:
| Alt text | Verdict |
|---|---|
| (empty) | Missed opportunity for a useful image |
| image123 | Meaningless |
| blog SEO tips SEO guide best SEO keyword | Keyword stuffing, avoid |
| screenshot | Too vague |
| Screenshot of the Rank Math sitemap settings screen | Good: specific and useful |
Google’s documentation shows the same pattern: “puppy” is better than nothing, but “Dalmatian puppy playing fetch” is best.
How to write good alt text
- Describe what is in the image. What would you tell someone on the phone?
- Add the context. Why is this image in this post? A screenshot of a settings screen should say which screen.
- Keep it short. One short sentence or phrase is usually enough.
- Skip “image of”. Screen readers already announce that it is an image.
- Use your topic only if it fits. If the image genuinely shows your topic, the words will appear naturally.
Avoid keyword stuffing
Google advises: “Avoid filling alt attributes with keywords.” It warns this “results in a negative user experience and may cause your site to be seen as spam.” Write for a person first.
Alt text examples for common blog images
- Featured image with text: repeat the key text, such as “How to write a meta description guide cover”.
- Screenshot: “WordPress Settings Permalinks screen with Post name selected”.
- Product photo: “Black laptop stand holding a 14-inch laptop on a wooden desk”.
- Chart: summarise the key point, such as “Bar chart showing traffic rising from 100 to 400 visits per month”.
- Photo of you: “Nayan Dhumal working at a laptop” (with your own name).
Decorative images
Some images are purely decorative, such as a divider line or a background pattern. These can have empty alt text, so screen readers skip them. Most images in blog posts carry information, though, so they should have a description.
How to add alt text in WordPress
- Click the image in the block editor.
- In the right sidebar, find the Alternative text box under the block settings.
- Type your description.
- Update or publish the post.
You can also add alt text in the Media Library: open the image, fill in the Alternative Text field and save. This sets it for future uses of that image, but images already placed in posts may keep their old text, so check those too.
Alt text and your focus keyword
SEO plugins such as Rank Math check whether your focus keyword appears in at least one image’s alt text. If one of your images genuinely shows the topic, include it naturally. If it does not, do not force it. A truthful description is better than a keyword that does not match the image.
For other image basics, such as file size, format and file names, see my guide to optimising images for SEO. For creating the images themselves, see my Canva tips for blog images.
Alt text vs image title vs caption
| Field | Who sees it | Purpose |
|---|---|---|
| Alt text | Screen readers, search engines, and visitors when the image fails to load | Describes the image |
| Caption | Every visitor, under the image | Adds context or credit |
| Title | Some browsers on hover | Rarely needed |
Alt text is the one that matters most for accessibility and search.
Frequently asked questions
How long should alt text be?
Short. A phrase or one sentence is usually enough. Describe what matters in the image without writing a paragraph.
Does alt text help SEO?
Google uses alt text, along with the page content, to understand images. Useful, specific alt text helps. Keyword stuffing does not.
Should every image have alt text?
Every image that carries information should. Purely decorative images can have empty alt text so screen readers skip them.
Should I start alt text with “image of”?
No. Screen readers already announce that it is an image. Start with the description itself.
Can I use the same alt text on every image?
No. Each image shows something different, so each needs its own description.