When you upload an image to your website, blog, or online store, you’re putting more than just a picture on the page. Behind the scenes, that image carries a small but powerful piece of code called ALT text (alternative text). This tiny text snippet doesn’t show up to most visitors, but it plays a huge role in how Google understands and even ranks your images in search results.
Alt text may seem simple, but when used correctly it can improve your SEO, make your site more accessible to people with visual impairments, and help your content appear in Google Image Search, an increasingly popular way people find information online. In this guide, we’ll explore what ALT text is, why it matters for SEO, how to write it well, and how to add it in practice across different platforms.
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| How to Add ALT Text for Google Images SEO |
What is ALT Text?
ALT text is a short written description that tells search engines and assistive technologies what an image is about. When you include an image in an HTML page, you add a line like:
<img src="sunset-dunes.jpg" alt="Golden sunset over sand dunes on a beach">
The words inside the alt="" are what Google and screen readers read to understand the image. Without this description, images are invisible to machines; they cannot “see” pictures like humans do. This makes alt text essential for both search engines and accessibility tools like screen readers for visually impaired users. (HubSpot Blog)
Why ALT Text Matters for Google SEO
You might wonder why a short text for an image matters so much. The truth is that search engines rely on signals like alt text to make sense of visual content.
Google uses a combination of alt text, file names, surrounding page content, and even computer vision algorithms to understand what an image shows. Alt text gives Google the cleanest, most direct clue about your image, which improves the chances of your image showing up in relevant searches. (Search Engine Journal)
While alt text does not magically boost your entire page ranking in regular web search results, it does help images appear in Google Image Search, where many users look for pictures related to products, tutorials, recipes, and more. (Search Engine Journal)
For example, if you have a blog post about “mountain biking trails,” and you include images of scenic routes, properly optimized alt text can help those images show up when someone searches “mountain biking trail images.” This increases overall visibility and brings more traffic to your site. (Digital360)
Accessibility: A Crucial Benefit
Alt text isn’t just about SEO. It’s also about making the internet inclusive.
People who are blind or visually impaired use screen readers, software that reads aloud the content of web pages. When an image has descriptive alt text, the screen reader can communicate what the image shows. Without alt text, these users miss out on important parts of the content. One report notes that alt text is critical for accessibility, especially for those relying on assistive technology. (Saad Raza SEO)
Even for users without disabilities, if an image fails to load because of slow internet or server issues, the browser displays the alt text instead, giving context rather than a broken blank space. This enhances the user experience, which indirectly supports SEO by lowering bounce rates and keeping visitors engaged. (Digital360)
Writing Good ALT Text: Best Practices
Writing alt text isn’t about stuffing a bunch of keywords or repeating phrases from your page. It’s about clear, concise descriptions that match the image and the context of the content around it.
Here’s how to do it well.
Be Descriptive and Specific
Your alt text should describe what the image genuinely shows. For example, if the image is of a red bicycle parked near a café table, a good alt text would be “red bicycle parked beside a café table on a cobblestone street.” This helps both humans and search engines understand exactly what the image depicts. (Similarweb)
If the image serves a function—like a “play” button or a graphic showing a download link—the alt text should describe the function rather than the appearance. For example: alt="play video about SEO tips". (Similarweb)
Keep It Concise
While it’s good to be descriptive, avoid long sentences. Most screen readers cut off alt text beyond about 125 characters, so aim to describe the image in a short, clear phrase or sentence. Something around 5 to 15 words is often enough. (Seokhana)
Shorter text is easier for users and search engines to process, and it avoids clutter in the code. Imagine trying to read a long paragraph in place of a simple image description—it doesn’t help anyone. (Similarweb)
Include Relevant Keywords Naturally
Including a relevant keyword once or twice can help Google associate your image with user search terms, but it needs to be natural. You should never force keywords into alt text in a way that feels unnatural or spammy. For example, alt="affordable blue running shoes for men" is fine if the image truly shows those shoes and relates to content on your page. (HubSpot Blog)
What you shouldn’t do is something like alt="shoes running affordable blue buy now sale shoes cheap". Not only does that feel spammy, but Google may ignore such over-optimized text. (Digital360)
Skip Redundant Phrases
Phrases like “image of” or “picture of” are unnecessary. Screen readers already know it’s an image. So instead of writing alt="image of Eiffel Tower at night", you can simply write alt="Eiffel Tower illuminated at night". (Similarweb)
Use Unique Descriptions
Every image on a page should have its own unique alt text. If all alt text reads the same (like “header image” or “product”), search engines miss important information about individual images. Unique, descriptive alt text improves the chance that each image is indexed correctly. (Digital360)
When Not to Use ALT Text
Not every image needs a rich alt text. Some images are purely decorative—like background patterns, accents, or spacer graphics—that add no real meaning to content. For these, it’s better to leave the alt attribute empty like this: alt="". This tells screen readers to skip the image entirely, focusing attention on meaningful content instead. (Similarweb)
This is important because adding irrelevant or filler text for decorative images can confuse both users and search engines. Only images that have semantic value or meaning should be described. (LinkedIn)
How to Add ALT Text on Different Platforms
Adding alt text varies depending on the platform you use. Here’s a quick look at how it works in common environments.
On a Website (HTML Code)
If you’re editing HTML directly, adding alt text is simple. In your image tag, include the alt attribute:
<img src="forest-waterfall.jpg" alt="lush green forest waterfall in morning light">
Make sure the alt attribute is inside the <img> tag and contains your descriptive text.
In WordPress
If you use WordPress, you can add alt text from the Media Library. After uploading an image, click on it and you’ll see an Alt Text field on the right side. Just type in your descriptive text there. This will automatically include the alt text in the HTML when the image is embedded. (Seokhana)
In Google Docs (for accessibility)
Even documents that are shared publicly can benefit from alt text. In Google Docs, right-click an image, choose Alt Text, and write your description in the field provided. Documents with good alt text are more accessible to readers using assistive technologies. (California State University, Northridge)
In E-commerce Platforms
Platforms like Shopify, Etsy, or product managers often allow alt text in the image settings or product editors. Look for fields usually labeled Alt Text, Image Description, or something similar. Here, you can tailor alt text to both describe the product and support relevant search terms when appropriate.
Common Mistakes to Avoid
Even seasoned web creators slip up when writing alt text. Here are some pitfalls to watch out for.
Leaving Important Images Blank
Many people skip alt text for images they think are “self-explanatory” or “not important.” But if the image adds meaning to your content, it deserves a good description—even simple ones help Google understand your page better. (LinkedIn)
Stuffing Keywords
Overusing keywords in alt text is a common SEO mistake. Google will penalize or ignore content that feels unnatural and spammy. Align your descriptions with what the image truly shows and only include relevant search phrases where they fit naturally. (Search Engine Journal)
Repeating the Same Alt Text
Sometimes sites use the same alt text for many images. This diminishes the clarity and relevance of each image. Alt text should be specific to each image’s content and context. (Digital360)
Ignoring Page Context
Alt text should not only describe the image itself but also connect to the surrounding content when appropriate. If an image supports a particular paragraph or idea, reflect that in the description to reinforce topical relevance. (LinkedIn)
The Big Picture: How ALT Text Fits Into SEO
Alt text is not a silver bullet that guarantees top rankings, but it is a valuable piece of the image SEO puzzle. When combined with thoughtful content, good page structure, relevant keywords, and user-friendly design, optimized alt text helps Google and users understand your content better.
This leads to better indexing, improved visibility in Google Image Search, and a smoother browsing experience for all visitors. Put simply: adding clear, relevant alt text is both a technical and human-centered practice that benefits the reach and accessibility of your website.
Final Thoughts
Good alt text is about clarity and context. It strengthens your SEO, makes your content accessible to a wider audience, and gives search engines the signals they need to index your site effectively. Take the time to write thoughtful, descriptive alt text for meaningful images, and your site could gain traction in image search results, improve engagement, and reach more users overall.
Alt text may be small, but it carries big power in a visual internet. Use it wisely, with care, and with users in mind.
Related Questions & Answers
What is ALT text in Google Images SEO?
ALT text is a short written description added to an image’s HTML code. It helps Google understand what the image represents and improves visibility in Google Images. ALT text also supports accessibility by describing images to screen readers for visually impaired users.
Why is ALT text important for SEO?
ALT text helps search engines index images accurately and associate them with relevant search queries. Properly written ALT text can increase image search traffic, improve page relevance, and support overall on-page SEO. It also enhances user experience and accessibility compliance.
How do I add ALT text to an image?
ALT text is added within the image tag in HTML using the alt attribute. In CMS platforms like WordPress, you can add ALT text directly in the media library or image settings. Always describe the image clearly and naturally for best SEO results.
What should good ALT text include?
Good ALT text should accurately describe the image content in simple language. It should include a relevant keyword only if it fits naturally. The description must be specific, helpful, and readable, avoiding unnecessary words or generic phrases like “image of” or “picture of.”
How long should ALT text be?
ALT text should usually be under 125 characters to ensure screen readers read it fully. Short, meaningful descriptions work best. Focus on clarity rather than length, describing the main subject and context of the image without stuffing multiple keywords or extra details.
Can ALT text improve Google Images ranking?
Yes, ALT text is a strong relevance signal for Google Images. When combined with quality images, descriptive filenames, and surrounding text, ALT text helps images rank higher for relevant searches. While not the only factor, it plays a significant role in image SEO.
Should keywords be used in ALT text?
Keywords can be included in ALT text if they naturally describe the image. Avoid keyword stuffing, as it can harm SEO and accessibility. The primary goal is to describe the image accurately, with keywords supporting relevance rather than dominating the description.
What are common ALT text mistakes?
Common mistakes include leaving ALT text empty, stuffing keywords, using vague descriptions, or repeating the same ALT text for multiple images. These errors reduce SEO value and accessibility. Each image should have unique, descriptive ALT text tailored to its specific content.
Is ALT text required for decorative images?
Decorative images that add no informational value can have empty ALT attributes. This tells screen readers to skip them, improving accessibility. However, important images that convey meaning or context should always include descriptive ALT text for SEO and usability purposes.
How does ALT text help accessibility?
ALT text allows screen readers to describe images to visually impaired users. This makes content more inclusive and compliant with accessibility guidelines. Google values accessible websites, so proper ALT text indirectly supports SEO while improving user experience for all audiences.
Does ALT text affect page load speed?
ALT text itself does not impact page load speed. However, well-optimized images combined with proper ALT text contribute to better overall performance and SEO. While ALT text is textual, image file size and format are what primarily affect loading speed.
Should every image have unique ALT text?
Yes, each meaningful image should have unique ALT text that matches its content. Duplicate ALT text across multiple images confuses search engines and reduces relevance. Unique descriptions help Google understand image differences and improve visibility in Google Images search results.
How does ALT text relate to image filenames?
ALT text and image filenames work together for image SEO. Filenames describe the image at the file level, while ALT text explains it in context. Using both consistently helps Google better understand and rank images for relevant image search queries.
Can ALT text replace image captions?
No, ALT text and captions serve different purposes. ALT text is mainly for search engines and screen readers, while captions are visible to users. Both can be optimized, but ALT text should not repeat captions word-for-word unless it accurately describes the image.
How can I audit ALT text for SEO?
You can audit ALT text using SEO tools, browser extensions, or CMS media libraries. Check for missing, duplicate, or poorly written ALT text. Updating ALT text with accurate descriptions and relevant keywords can quickly improve Google Images visibility and accessibility.