What Are Alt Attributes and Why They Matter?

Every image on your website should have an alt attribute. Yet nine out of every ten small business websites I audit in Pune have images with either missing alt text or the useless placeholder "image123.jpg" that no one bothered to fix. This is one of the easiest on-page fixes in SEO, and it also happens to be a legal requirement for accessibility in many countries.

I will walk you through exactly what alt attributes are, how they work in HTML, why they matter for both SEO and accessibility, and how to write ones that actually earn their place. Real examples throughout, including the exact alt text I use on client sites.

What is an alt attribute?

An alt attribute is an HTML attribute inside an image tag that provides a text alternative for the image. It looks like this in code:

<img src="dental-clinic-baner.jpg" alt="Dr Sharma performing a dental checkup at Sai Clinic Baner">

The alt="..." portion is the alt attribute. The text inside the quotes is called the "alt text" or sometimes "alt tag" (though technically the term "tag" is wrong, since alt is an attribute, not a tag). All three terms refer to the same thing: the text you write to describe an image.

The alt attribute serves three specific purposes:

1. It is read aloud by screen readers to visually impaired users, so they understand what the image shows.
2. It is used by search engines to understand what the image is about, which affects how the image appears in Google Image search and how the surrounding page gets indexed.
3. It appears in place of the image when the image fails to load (broken links, slow connections, users blocking images).

Why alt attributes matter for SEO

Google cannot see images the way humans do. It uses machine vision to guess what an image contains, but that guess is imperfect. Alt text is your direct signal to Google saying "this image shows exactly this." Without alt text, Google's machine vision does its best, but you lose all the ranking signal that specific descriptive words would provide.

For a Pune orthodontic clinic I worked with, we had 40 photos of teeth alignment cases with generic filenames like "IMG_0234.jpg" and no alt text. Google was indexing them as generic "teeth" images, competing against millions of others. After we renamed the files and added specific alt text like "invisalign clear aligners case study upper teeth," the images started appearing in Google Image search for those exact queries. Image search brought consistent visits from patients who were researching before booking.

Alt text also feeds the overall relevance signal for the page. If your page is about "wedding photography in Pune" and every image has alt text confirming that topic ("bride and groom pheras Pune wedding," "haldi ceremony candid photograph"), you reinforce the page's topical focus. The words in alt text are content, just like the words on the page. Google reads them all.

Alt attributes will not push a bad page to page one on their own. But combined with all the other on-page fundamentals I cover in my on-page SEO checklist for 2026, they are a compounding advantage that most small businesses ignore.

Why alt attributes matter for accessibility

Roughly 285 million people worldwide are visually impaired. Many use screen readers, software that reads webpage content aloud. When a screen reader encounters an image with alt text, it reads the alt text so the user knows what is there. When it encounters an image without alt text, it either announces "image" (unhelpful) or reads the filename ("IMG-2345-final-final.jpg", worse).

For a portfolio site or blog, missing alt text just makes the experience frustrating for blind users. For a business site, it can mean losing customers. For government, healthcare, or educational websites in many countries (including under India's Rights of Persons with Disabilities Act 2016), inaccessible websites can also be a legal liability.

Beyond blind users, alt text also helps people on slow connections who have images disabled, users on old browsers, and voice assistants that summarise web pages aloud. It is the most universally beneficial single piece of extra text you can add to your site.

How to write good alt text

There is no single formula, but there is a clear pattern I follow with every client. Good alt text describes what is in the image and its purpose on the page, in the fewest words that convey both.

Rule 1: Describe what is actually there

Look at the image and describe what a person seeing it for the first time would notice. Not what you know about the image, but what is visually present.

Bad: alt="best dental clinic"

Good: alt="Dental clinic reception with patient waiting area and receptionist at desk"

Rule 2: Include relevant keywords naturally, do not stuff

If the page is about "dental veneers in Pune" and the image shows veneers being applied, mention veneers in the alt text. But do not stuff every keyword you want to rank for.

Bad: alt="dental veneers Pune best dentist teeth whitening smile makeover Baner Kothrud Aundh"

Good: alt="Dentist bonding porcelain veneers on upper front teeth"

Rule 3: Keep it short, aim for 8 to 15 words

Screen readers read the full alt text aloud. Anything longer than a sentence gets tedious. Most screen readers truncate at around 125 characters, so treat that as your hard ceiling.

Rule 4: Do not start with "image of" or "picture of"

Screen readers already announce "image" before reading the alt text. Starting with "image of" is redundant. Just describe the image directly.

Bad: alt="Image of a woman getting her hair styled"

Good: alt="Woman getting her hair styled at a salon"

Rule 5: For decorative images, use an empty alt attribute

If an image is purely decorative (a background pattern, a divider line, a stylistic flourish), give it an empty alt attribute like this: alt="". This tells screen readers to skip it. Never leave the alt attribute out entirely on decorative images. Screen readers handle a missing attribute differently from an empty one.

Rule 6: For logos, describe the logo's purpose

Your business logo does not need a fluffy description. It needs the business name. For a header logo linking to the homepage, the alt text should be the business name.

Good: alt="Shreyas Bagal" or alt="Sai Dental Clinic logo"

Rule 7: For informational graphics, summarise the information

If your image is a chart, a diagram, or a table saved as an image, the alt text should convey the key information. If the information is too complex for alt text, keep the alt brief and add the full description in the surrounding text or a caption.

Bad: alt="Chart"

Good: alt="Chart showing 60 percent traffic increase after SEO work over 6 months"

Real alt text examples I use on client sites

Here are actual alt text examples from live client work. Notice how each one describes the image specifically, uses natural language, and includes relevant context without keyword stuffing.

• Dental clinic before and after image. alt="Patient smile before and after dental veneers treatment"
• Restaurant food photo. alt="Butter chicken served in copper karahi with garlic naan"
• Salon service photo. alt="Hair stylist doing keratin treatment on long dark hair"
• Team headshot. alt="Dr Priya Sharma dental surgeon"
• Blog post cover image. alt="Google Search Console dashboard showing keyword clicks and impressions"
• Product photo for boutique. alt="Red banarasi silk saree with gold zari border front view"
• Location photo. alt="Sai Clinic exterior view from Baner main road"
• Chart or graph. alt="Bar chart of monthly Google Business Profile calls January to June 2026"

Common alt attribute mistakes to avoid

Leaving alt attributes empty on content images

Empty alt is only for decorative images. Content images (photos of your products, services, team, work) always need descriptive alt text. Leaving them empty tells Google the image is not important, which is the opposite of what you want.

Using the filename as alt text

Some content management systems auto-fill alt text with the filename. So you end up with alt="IMG_20240815_143022.jpg". This is worse than nothing. Always manually write descriptive alt text for every image you upload.

Keyword stuffing

Cramming five variations of your target keyword into every image alt attribute triggers Google's spam signals. It also makes the alt text useless for screen reader users. Write one clear, natural description per image.

Copy-pasting the same alt text on similar images

A gallery of 10 product photos with identical alt text "wedding photograph" wastes the opportunity. Each image should have unique alt text describing what makes it different. "Bride putting on jewellery," "groom entering wedding venue," "couple exchanging rings."

Writing alt text that duplicates the surrounding caption

If your image already has a caption that describes it, do not repeat the caption in the alt text. Screen readers will read both, and the user hears the same information twice. Vary the wording, or use empty alt if the caption fully describes the image.

Ignoring text in images

If your image contains text (a testimonial screenshot, an infographic with words, a poster), the alt text should include that text. Otherwise a screen reader user misses everything the image was trying to say.

How to check your existing site for alt attribute issues

Most websites I audit have some mix of missing alt attributes, filename alt text, and generic placeholders. Here is how to find and fix them systematically.

1. Run my free website SEO checker. It scans your homepage for images with missing or generic alt text and flags them in the report. Fix everything it lists first.
2. Right-click any image on your page and select "Inspect" in your browser. Look at the image tag. If you see alt="" on a content image, or no alt attribute at all, that image needs fixing.
3. Use a screen reader to browse your own site. On Mac, turn on VoiceOver (Cmd + F5). On Windows, use Narrator or NVDA. Listen as the screen reader announces your images. If it says "image" and moves on, your alt text is missing. If it reads a filename, your alt text needs to be replaced.
4. Check your WordPress media library. Every image in the library has an alt text field. Bulk-edit or go image by image to add descriptive alt text.
5. Check images inside CSS backgrounds separately. CSS background images do not have alt attributes. If they carry meaning, move them to img tags with proper alt text. Purely decorative CSS backgrounds are fine as they are.

Alt attributes for different image types

Product images (e-commerce)

Include product name, key attribute (colour, size, material), and view angle where relevant. Example: alt="Blue cotton kurta with white embroidery front view".

Blog post cover images

Describe what is in the image, not the blog post title. Example for a post titled "How to Rank in Google Maps," a cover showing a laptop with Google Business Profile open: alt="Google Business Profile dashboard open on a laptop screen".

Team member photos

Use the person's name and role. Example: alt="Shreyas Bagal freelance digital marketer". Do not describe physical appearance.

Location and interior photos

Include location context. Example: alt="Salon reception area with white marble counter and welcome desk".

Testimonial screenshots

Transcribe the key text of the testimonial in the alt. Example: alt="Testimonial: Shreyas helped my dental clinic move from position 59 to top 5 in two months".

Icons and small UI elements

If the icon is decorative and next to a text label, use empty alt. If the icon is the only thing (like a magnifying glass search button with no text), give it a purposeful alt like alt="Search".

Related on-page SEO guides

Alt text is one piece of a bigger on-page picture. These guides walk you through the rest:

• Complete image SEO optimization guide — filenames, compression, lazy loading, structured data.
• Free on-page SEO checklist for 2026 — the full checklist including alt text.
• What is on-page SEO — the fundamentals overview.
• How to write title tags that rank — sister topic for page metadata.
• How to write meta descriptions — the other visible metadata Google reads.

Frequently asked questions

What is the difference between alt attribute and alt text?

There is no difference. Alt attribute is the technical HTML term (the alt="..." part inside an image tag). Alt text is what you write inside that attribute. People use both terms interchangeably. When an SEO article says "add alt text to your images," it means fill in the alt attribute value. When a developer says "this image has no alt attribute," they mean the alt="..." is missing entirely.

Do I need alt text on every image?

Every content image needs alt text. Decorative images (patterns, dividers, background flourishes) should have an empty alt attribute (alt="") so screen readers skip them. Never leave the alt attribute out completely on decorative images, and never write "image" or "photo" as alt text. For a Pune clinic site I audited, adding proper alt text on 40 service photos lifted image search traffic by 22 percent in eight weeks.

How long should alt text be?

Aim for 8 to 15 words that describe what is in the image and its purpose on the page. Screen readers read the full text aloud, so anything longer becomes tedious. If your image needs a longer explanation (a chart, a diagram), keep the alt short and put the detailed description in a caption or surrounding text. Never exceed 125 characters, which is roughly where most screen readers truncate.

Does alt text really help SEO?

Yes, in two ways. First, Google uses alt text to understand what an image shows, which drives Google Image search traffic. Second, alt text is one of the signals Google uses to understand the page's overall topic. For a Pune clinic's before-after photos, alt text like "dental veneers before and after treatment at Baner clinic" brought consistent image search visits. Alt text will not rocket a bad page to page one, but it is a free easy fix that most sites still skip.

Can I use the same alt text for similar images?

No. Every image needs unique alt text that describes what that specific image shows. A gallery of 10 product photos labelled "red saree" repeatedly signals thin, duplicated content. Instead write "red silk saree front view," "red silk saree pallu detail," "red silk saree draped on model." Run your website through my free SEO checker to see which images are missing unique alt text.

Your next step

Open your homepage. Right-click your first image and inspect it. Fix the alt text if it is missing or generic. Then run my free SEO checker to find every other image that needs the same treatment.