How to Write Alt Text for SEO and Accessibility Wins

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Alt text (short for “alternative text”) is not an SEO tool, it’s an accessibility tool. But it can also help with SEO.

It’s the text that is read to a user who cannot see an image, or that is shown if an image has a glitch and can’t load. It is meant to be descriptive text to replace the image.

My grandma is blind and I use a screen reader for my ADHD, so I’m obsessed with good alt text. Seriously, if there’s no alt text or it’s a keyword stuffed nightmare, I’m leaving the website.

Unfortunately, most SEOs teach bloggers to just copy and paste the keyword into the alt text for every single image in a post.

I’m here to undo their sins and help y’all make your website more accessible to blind users – and to Google. Remember, Google doesn’t have eyes. It reads the alt text just like a disabled user to understand the context of an image.

If you skip alt text for an image, you are hurting your disabled users and hurting Google’s ability to understand what your image is of. This is especially true for infographics, stats, and descriptive images like a beach to convince someone to visit a place.

I’m going to teach you how to do alt text properly, as a disabled person who relies on alt text myself.

How to Write Great Alt Text

Alt text is actually incredibly easy to write. It only requires two elements to be great:

Describe what the image is of
Describe how it’s relevant to the post/where it’s put in the post

Alt text should replace the need for seeing the image.

For example if I told you there was a photo of a beach beneath this sentence in this blog post, you’d be confused.

Why is there a beach in a blog post about alt text? What type of beach? Is it rocky or sandy? Is it swimmable? Is it sunny or stormy? And what the heck does a beach have to do with alt text?

Those are all questions your alt text should answer.

Perhaps it’s: “Sunny day on the beach in Mexico with soft sand underneath a red striped beach blanket. A happy woman reads a blog post on her iPad with alt text that properly describes images for her vision impairment.”

Now you understand the image a lot better, right?

That’s what you should endeavour to do with all of your alt text.

Remember: describe everything that’s relevant. Assume the person is completely blind and has never encountered the pictured thing before.

This is especially true for screenshots.

Many people just say “homepage of Google Analytics”. …ok? But what if that person has never been to that webpage before or has never seen it. What about the homepage matters? Why did you include it?

Be specific and descriptive.

You don’t need to describe every leaf on a tree, but if the tree is important, you should say that there’s a tree there.

I give more examples of great alt text in this video tutorial:

Alt Text for Infographics or Diagrams

Many bloggers use infographics, graphs, or other diagrams on their site to help make information easier to digest. Or to allow users to download the information for later.

But many users can’t even read the information to begin with.

I’ve been on so many packing list blog posts that never write out the packing list; they just pop it in a Canva checklist and embed that on the page as a .png.

Well, I can’t read that with my screen reader so now the whole post is useless to me.

If a user needs to see the content to understand it, you need to describe it.

A good rule of thumb is that any text on an image should also be included in the alt text. This goes for infographics that are full of writing, too.

Don’t skimp because you’re lazy. Your users deserve all the information in the post, regardless of their disabilities.

How to Add Alt Text to Image in Your Media Library

You can add alt text to images in 2 ways: via the Media Library (this will apply it sitewide to new insertions of the image in blog posts/pages), and in specific posts (this will only affect the alt text in that post/page).

To add alt text in your Media Library and click on any image.

This will bring up a pop up of the image with all of its information. Notably, it shows the alt text box at the top of the fillable sections, as shown here:

Screenshot of an image in the Media Library on WordPress full screen that features the image and its information such as the title and file size. A red arrow and circle highlight the "alternative text" field which has writing in it describing he image as "How to Make Hyperlinks in WordPress".

Type in your alt text and then close out of the pop up, or move to the next image using the controls on the top right corner. This will automatically save the alt text for the image.

This does not retroactively apply the alt text to every use of the image in your blog. Those images are overridden by whatever was done at the post level.

If they were added to a post with no alt text, that empty alt text will override the new Media Library alt text.

I typically don’t add alt text in the Media Library unless I’m generically describing an image. That’s because the context needed will change per blog post (yes, you should be reusing images across blog posts). I don’t want to have to delete extra text.

How to Add Alt Text to Images in Posts

You can also add alt text inside of a post/page in WordPress by clicking on the image block. The lefthand sidebar will show you an area titled “alt text” for you to add it in:

Screenshot of a blog post editor in WordPress with a large image on the left side of the screen and a red arrow and circle highlighting the right side bar section for "alternative text" that is currently blank as the author writes the post.

This will vary by website, as different editors like Elementor have the area for alt text in different places. Every website builder has an area to add alt text. It may take you a moment to find it, but it is certainly there. I have never encountered one that doesn’t have it at all.

If you’re not sure where it is, Google your theme or website platform and “alt text” to find it.

When you edit the alt text at the post level, it only applies to that specific image in that specific post.

Even if you added the same image 4 times in the post, it would only apply the alt text you did to the first image to the first image.

I prefer to add alt text at the post level so I can be more specific with my context about why an image matters to that specific post. It allows me to see where in the post the image is.

I typically add my alt text right before I hit publish on a post, so this is an easy way to go through all my images at once.

Add this as the final step before inbound internal links in your content writing checklist.

Alt Text vs. Captions vs. Descriptions

Alt text is alternative text, or the text shown when an image cannot be seen or rendered. This is text meant to replace the image.

Captions show regardless of whether or not the image shows. This is text usually displayed below the image that adds context to help the user interpret the image, especially if it is not clear via the image or the text surrounding the image.

Descriptions are a longer form of alt text that are typically used to go into more detail than alt text can about an image. This is where you would add information like an incredibly long infographic description or writing out all the text on the screenshot of a PDF.

Many people just add this to the alt text rather than using the descriptions at all. They’re often more used internally with bloggers with notes for keywords for internal searches and noting where an image came from.

You can find all of these in the Media Library for each image:

Screenshot of the text fields beside an image in the Image Library on WordPress showing the "alternative text", "title", "caption", and "description" fields. Only the first two are filled out with "How to Create Jump Links with WordPress" for both.

How to Check Alt Text

Option 1: Code

You can check the alt text of your competitors, or your own site, by inspecting the code.

Right click on the image in question and select “Inspect”:

Screenshot of an image in a blog post for She Knows SEO with a pop up overlayed where the last option is highlighted that says "Inspect".

This will open a window of code for the whole page but highlight the specific code of the image you selected:

Screenshot of code highlighted in blue showing the image source code for an image in a She Knows SEO blog post to demonstrate how to find alt text in the code.

If you look for “alt=” you’ll find the alt text:

Alt text highlighted via "alt="A laptop displaying SurferSEO's AI writer tool with features to "Skyrocket your organic traffic", indicating an SEO strategy and content improvement workflow" in the code from the previous image that is the code from a She Knows SEO blog post image.

If there is no “alt=”, then the image is missing alt text.

Option 2: Ahrefs Chrome Extension

The code can get a bit messy and overwhelming. An easy, at a glance way to check the alt text of every image in a competitor’s post is with the free Ahrefs Chrome Extension.

Turn on the extension, click “Images” and you’ll see all of the post’s images at a glance.

The extension highlights their alt text, title, URL, and shows a thumbnail of the image so you know which is which.

For example, on the one click AI blog writer post, this is what the alt text looks like in the extension’s preview:

Screenshot of the Ahrefs Chrome Extension "Images" section showing three images from the She Knows SEO one click AI writer blog post that shows the alt text, title, and URL for each image beside a thumbnail of the image. In this case, it shows the images for SurferSEO's AI, Koala AI, and Reword AI along with their complete alt text.

Option 3: With a Screenreader

Every Mac has a screen reader built in called VoiceOver.

Hit Cmd + F5 to activate it and the screen reader will work on whatever you move the mouse over, or start from the beginning of the post if you click the first word.

This is what I use as a screen reader, although there are better paid software out there for visually impaired individuals. But it’s an easy free option to check how alt text is read for yourself.

How to Automate Your Alt Text

Whether you’re short on time or have a disability that makes writing a challenge, I’ve got you! We can automate your alt text together with my free custom GPT.

She Knows Alt Text custom GPT as seen in ChatGPT on a mock up computer screen. Shows a blue icon featuring a dark blue picture with white mountains, text saying "She Knows Alt Text" and 4 options for prompts to give the GPT to get started.

She Knows Alt Text is a custom GPT that I’ve trained on my exact methods for writing alt text – including adding in keywords for context in a post! – so you can get great alt text quickly.

All you need to do is get a paid ChatGPT subscription and you have unlimited use.

You can find it in the GPT store or directly at this link:

Screenshot of "she knows" search in the GPT store bringing up the "She Knows Alt Text" GPT and it's over 5,000 uses.

Upload a photo or paste a URL to a post on your site with photos (note: some security plugins and CDNs block ChatGPT, so it may not be able to fetch information with a URL for all sites). Then the GPT will ask you for a keyword you’re targeting.

The GPT actually looks at the image and interprets what it’s of, looks at the file names for extra context clues, and uses any keyword information you’ve provided to create 2-3 sentence alt text that describes the image and it’s context.

I used it to write the alt text for all of the images in this blog post!

Adding SEO Keywords to Alt Text

While you shouldn’t keyword stuff your alt text and make every image just say “best beaches in Croatia”, you can add keywords to some of your alt text.

The key is to do it naturally.

Pretend every user can see your alt text. Does it look normal to have: “Croatian beaches | best beach Croatia | Split beach”? No it doesn’t. Especially if you have that for every single image.

But it looks totally normal to have: “Rocky beach in Croatia with turquoise waters and distant rocky islands on a sunny day.”

You’d definitely want to be more specific about where the beach is, but it’s more natural and readable for a user.

Add your primary keyword and secondary keywords to alt text sparingly. Focus on getting the point across first, then building in your keywords if you can do so naturally.

Using keywords in alt text does count towards your total keyword use. Google doesn’t like high densities of keywords because it looks like you’re trying to game the system. So be sparing.

Conclusion

Great alt text takes a few extra minutes of your time.

Many bloggers feel it’s not worth that extra time because they could be doing something else that feels more productive. But alt text is essential.

Disabled users are so used to getting the short end of the stick with missing content or context.

And it sucks.

Over 16% of the world is disabled. And over 70% of those individuals will leave a website if it’s not accessible to them. Like I said earlier, I’ll leave a keyword stuffed alt text website on principle, even if I’m not using my screen reader that day.

Those extra minutes will make someone’s day massively. And get you a die hard fan who will keep coming back for more because they know you care about them.

And anecdotally, I can say that when I audited my content and added alt text to all my images, I saw my rankings improve with Google. This was long before I did any SEO properly so I can’t even credit a keyword with it otherwise.

But the point isn’t Google. It’s helping our users.

Alt text isn’t the only way to make your site accessible. I have a full checklist post here to help you make your website more accessible for users – and no, you don’t need any fancy plugins or to be a coder. In fact, you need to stop adding code and plugins that break your accessibility.