Does Alt Text on Photos Help SEO? How to Write It
Learn what alt text is, whether it helps your website show up in Google, and how to write it for your photos, with plain examples and a simple checklist.
Yes, alt text helps. Alt text (short for alternative text) is a short written description attached to a photo on your website. Google says it is the most important attribute for giving search engines information about an image, and it also lets people who can’t see the photo understand it. It supports search engine optimization (SEO), which is the work of making your site easier for Google to understand and show to the right people. It is not a trick. Write it for people first, and search engines benefit as a result.
This guide is for business owners who have never hired an SEO or touched the code behind their site. You will learn what alt text is, how to write it, what to leave blank, and how to check the photos you already have.
TL;DR
- Alt text is a short description of a photo that screen readers read aloud and Google uses to understand the image.
- Describe what the photo shows and why it is on the page, in a short phrase or one or two sentences.
- Work in a keyword only when it fits naturally. Stuffing keywords can make a site look like spam.
- Decorative photos get empty alt text. Never just delete the alt attribute.
- Fix file names, missing descriptions and copy-pasted text first. Those are the most common mistakes.
What alt text is and where it shows up
Every photo on a web page is placed with a small piece of code. One part of that code can hold a description of the picture. That description is the alt text, sometimes called an alt tag or alt attribute.
Visitors rarely see it. It matters in three situations:
- A person who is blind or has low vision uses a screen reader, software that reads the page aloud. The screen reader reads your alt text in place of the photo.
- The photo fails to load, for example on a slow mobile connection. The browser may show the alt text where the picture should be.
- Google crawls your page. Google uses alt text together with computer vision and the rest of the page to work out what an image is about.
The first group is the reason alt text exists. The Ahrefs explanation of alt text describes it as mainly an accessibility feature that also gives search engines helpful context.
Does alt text help your Google visibility?
It can help in a few specific ways, and it is worth doing. It is not a magic switch, and nobody can promise a ranking from it.
It helps Google understand your photos. Google reads alt text as one signal about what an image shows. That matters if you want your pictures to appear in Google Images, which can be an extra way for people to find you.
It adds context to the page. Descriptive alt text adds meaning to images, which could improve how relevant the page looks for its topic. A page about kitchen remodeling with photos described as finished kitchens tells Google the same story as your headings do.
It works as link text when a photo is a link. If a photo links to another page, the alt text acts as the clickable words for that link, and it helps Google understand where the link leads.
It supports product and service photos. HubSpot notes that specific alt text on product images gives search engines context about when to show a product.
The honest summary: write alt text because it makes your site usable for more people. The search benefit comes along with it. Search Engine Land makes the same point, that alt text can help SEO, but you shouldn’t write it only for SEO.
How to write good alt text for a photo
Start with one question: if someone could not see this photo, what would they need to know to get the same value from the page?
Describe the photo’s purpose, not every detail
Google’s own writing guide says alt text should briefly summarize the image’s purpose, using a short phrase or one or two sentences. Microsoft’s style guide agrees that good alt text is about interpretation and judgment, not describing every pixel.
The same photo can need different alt text on different pages. Say you own a landscaping company and have a picture of a stone patio with a fire pit:
- On a patio services page: “Stone patio with a built-in fire pit and seating wall in a Novi backyard.”
- On a blog post about fall yard cleanup: the photo may not belong at all, or it may be decorative.
Section508.gov, the U.S. government’s accessibility resource, says alt text should refer to the relevant content the image provides rather than simply describing how it looks.
Keep it short
There is no official character limit, but the common guidance is clear:
- Microsoft Learn suggests staying within 150 characters.
- HubSpot recommends fewer than 125 characters because screen readers tend to stop reading near that point.
- ta11y says to avoid going past 125 characters, while noting it is not a hard rule.
A safe habit: aim for under 125 characters, which is about one short sentence. WebAIM says typically only a few words are needed.
Skip “photo of” and “image of”
Screen readers already announce that something is an image. Starting with “photo of” or “image of” wastes the listener’s time. Both Google’s writing guide and web.dev tell writers to leave those words out.
Google’s guide also suggests capitalizing the first word and ending with a period. A period makes screen readers pause naturally after the description.
Use keywords only where they fit
Google recommends alt text that is useful and information-rich, with keywords used appropriately and in the context of the page. It warns that filling alt attributes with keywords creates a poor experience and may cause your site to be seen as spam.
Here is what that looks like for an Oakland County plumber:
| Style | Example | Verdict |
|---|---|---|
| Stuffed | “plumber Michigan best plumber Oakland County cheap plumbing water heater plumber” | Reads as spam to people and to Google |
| Empty effort | “IMG_4821.jpg” | Tells nobody anything |
| Too thin | “water heater” | Does not say why the photo is there |
| Good | “Plumber installing a tankless water heater in a basement utility room.” | Clear, natural, includes the service |
The keyword “water heater” appears in the good example because it belongs there, not because it was forced in. HubSpot’s advice is to include your target keyword only if it is easy to include and never to cram it into every image.
If you are not sure which words your customers actually type, our guide on finding the keywords your local customers search for walks through it without special tools.
Name the product when the photo is of a product
For a shop, Yoast suggests that a photo of a specific product can include the full product name and a product number in the alt text so it is easier to find. Keep it readable. A short product name plus one distinguishing detail is plenty.
What to do with decorative photos and photos with text
Not every image needs a description. Some images add nothing for a person who can’t see them: a thin divider line, a background texture, a stock photo that only sets a mood next to a paragraph that says everything already.
For these, the right answer is empty alt text, written as alt="" in the code. The World Wide Web Consortium (W3C), the group that sets web standards, says decorative images should have empty alt text so assistive technology can skip them.
There is one trap. Empty alt text is not the same as no alt attribute at all. When the attribute is missing, some screen readers read out the file name instead, which is useless and confusing. Web.dev puts the difference simply: an empty value means “skip this,” and a missing value means “nobody thought about it.”
The W3C also says that deciding whether a photo is decorative is a judgment only the author can make, based on why the photo is on the page. If you are unsure, web.dev’s advice is to add a description.
Schools and organizations that build interactive displays think about this constantly. Their design principles for interactive displays show why accessibility choices, including how images are described, matter to the people using them.
Photos that contain words
A photo of a sign, a coupon, or a flyer holds text. The W3C decision tree says:
- If the same words also appear as real text on the page, use empty alt text.
- If the words appear nowhere else, put them in the alt text.
The W3C alt decision tree covers these cases step by step. For a business owner, the practical lesson is to put important details like hours, prices and phone numbers in real page text, not only inside a picture. Real text is easier for everyone and for Google to read.
Charts, maps and complicated photos
For a chart or a map, give a short description in the alt text and the full explanation in the text on the page. Google’s writing guide recommends a short alt description and a longer written description nearby, and a data table for graphs. A service area map, for example, can have alt text saying it shows your service area, with the list of cities written out below it.
Photo file names and other quick wins
Alt text is one piece of getting a photo ready. Google also recommends short, descriptive file names, such as my-new-black-kitten.jpg instead of IMG00023.JPG, and says to avoid generic names like image1.jpg or pic.gif.
A quick routine before you upload any photo:
- Rename the file with a few plain words, separated by hyphens: stone-patio-fire-pit.jpg.
- Upload it to the page where it fits the topic.
- Write the alt text in the field your website editor provides.
- Check that the surrounding text and caption do not repeat the alt text word for word. Microsoft notes that a caption and alt text should not be redundant.
Writing a good caption is its own skill, and these tips on writing clear image captions are a good place to start.
Common alt text mistakes to fix first
Section508.gov lists the mistakes it sees most often. Here they are in plain terms, with what to do about each:
| Mistake | What to do instead |
|---|---|
| Alt text too short to be useful | Add what the photo shows and why it is on the page |
| Alt text too long, with extra detail | Cut it to the part that matters to the page |
| Describes how the photo looks, not why it is there | Describe the purpose, such as the service or product shown |
| Repeats the paragraph next to it | Say something new, or use empty alt text |
| File name used as alt text | Write a real description |
| Computer-generated descriptions that miss the point | Edit them by hand |
| Alt text in a different language than the page | Match the page language |
The source for that list is the Section508.gov guidance on meaningful alternative text. On automatic descriptions, ta11y explains that software often fails because it cannot know why the image is on the page, even when what it says is accurate. Use automatic tools for a first draft at most, and read every line yourself.
How to check the photos on your website
You do not need special software to start. Pick your five most important pages: usually your home page, your main service pages, and your contact page. Then:
- Open each page and list every photo.
- For each, ask: does this add information, or is it just decoration?
- Informative photos get a short, specific description. Decorative photos get empty alt text.
- Look at the file names. Rename anything that looks like a camera number.
- Read your alt text aloud. If it sounds like a list of search terms, rewrite it as a sentence.
If your website editor hides the alt field, ask whoever built the site where it is. It is a standard setting in most website builders.
Once your photos are sorted, the rest of the page matters too. Our on-page SEO checklist covers the other checks, and the guide on optimizing a service page for Google shows where photos fit in a page that is meant to bring in customers.
Our perspective
Most small business owners we meet have never been told that their photos need descriptions. The site was built, the photos went up, and nobody thought about the people who can’t see them or the search engines trying to read them.
We build alt text into the website from the start. When we design a page, we decide which photos carry information and which are decoration, and we write descriptions that say what the photo shows and why it is there. We also give photos plain file names. It is a small habit, and it saves you from a cleanup project later.
Our approach is to put SEO into the website while it is being built, not bolt it on afterward. That is why our sites include the essentials at launch, with a fixed price and no contract. We would rather you understand what is on your pages than depend on us for every small change.
If you already have a site, the best first step is the five page check above. If you want help, we are glad to look at it with you.
Eric Plotts
Want a website with this built in?
Blue Lake Web Design is owner operated by Eric Plotts in Novi, Michigan, and has served Metro Detroit and Oakland County since 2011. Our websites are built to load fast and include SEO basics, such as photo descriptions and clean file names, from launch. Our published prices are $899 for a three page website and $1,999 for eight pages, with a fixed quote for anything larger. You can see what is included on our website design pricing page.
If your current site needs more than photo fixes, look at our web design and redesign services. Want to talk it through? Call us at (248) 800-1855. You can also browse more plain-language guides on our web design and SEO articles page.
Alt text and local search
If you serve customers in one area, photos can quietly reinforce that. A real photo of your storefront, your truck, or a finished job in your town, with a plain description that names the place when it is relevant, gives visitors and Google an accurate picture of who you are and where you work.
Keep it honest and natural. “Finished basement remodel in a Royal Oak home” is useful. Repeating the town name in every photo on the page is not. For more on how Google shows nearby businesses, see our local SEO and Google Maps service.
A word about your business details: your name, address and phone number should be real text on the page, not only in an image. That keeps them readable for everyone, and consistent details across the web are covered in our guide to local citations.
FAQ
Does alt text on images help SEO?
Yes, it can. Google uses alt text, along with the page content and image analysis, to understand what a picture shows. It can help your photos appear in Google Images and adds context to the page. No one can promise a specific ranking from it, so write it mainly to be useful.
What is a good alt text for an image?
A good one is a short phrase or one or two sentences that says what the photo shows and why it is on the page. For example: “Owner measuring a window for a custom blind installation.” Leave out “photo of,” skip keyword lists, and stay under about 125 characters.
Should every image have alt text?
Every image should have the alt attribute, but not every image needs words in it. Web.dev explains that decorative images should have an empty alt attribute so screen readers skip them. Images that carry information should get a real description.
How long should alt text be?
Shorter is better. Guidance from Microsoft points to a limit of 150 characters, while others suggest 125. Treat 125 characters as a comfortable ceiling, and put the most important words first.
Can I use the keyword I want to rank for in my alt text?
Yes, when it describes the photo naturally. Google warns that stuffing keywords into alt text hurts the experience and can look like spam. If the keyword does not fit the photo, leave it out.
Recommended
Written by
Eric Plotts
Web designer and SEO consultant in Novi, Michigan. Building websites for small and mid sized businesses since 2011.More about Eric.