How to Check Image ALT Tags: Complete Guide for SEO

Images are an important part of modern websites. They can make content easier to understand, improve user experience, and help your pages appear in image search results. However, simply adding images to a website is not enough. Each important image should have useful and descriptive ALT text.

If you’re wondering how to check image ALT tags, this guide explains what ALT text is, why it matters, how to find missing ALT attributes, and how to fix common image SEO problems.

What Is an Image ALT Tag?

An image ALT tag, more accurately called the ALT attribute, is text added to an HTML image element to describe the image.

For example:

<img src="seo-audit.jpg" alt="SEO audit report for a business website">

The ALT text describes what the image represents. It can also provide useful information when an image cannot be displayed and helps people using screen readers understand the image.

Google recommends using descriptive ALT text and explains that it uses ALT text together with the page content and computer vision to understand the subject of an image.

Why Are ALT Tags Important?

ALT text has two major purposes: accessibility and image understanding.

1. Improves Accessibility

People who use screen readers may rely on ALT text to understand images on a webpage.

A descriptive ALT attribute provides a text alternative that explains the important information contained in an image.

2. Helps Search Engines Understand Images

Search engines cannot interpret every image exactly like a human does. ALT text gives additional contextual information about the image.

Google recommends writing useful, information-rich ALT text that describes the image naturally.

3. Helps When Images Cannot Load

If an image fails to load, its ALT text can provide users with information about what was supposed to appear.

4. Supports Image SEO

Well-written ALT text can help search engines understand images and their relationship to the surrounding content. This can be particularly useful for websites that receive traffic through Google Images.

However, ALT text should not be treated as a place to insert keywords repeatedly.

How to Check Image ALT Tags

You can check image ALT attributes manually or use an automated image ALT tag checker.

Method 1: Check ALT Text in Your Website’s HTML

One simple method is to inspect the HTML code of a webpage.

Look for an image element such as:

<img src="website-audit.png" alt="Website SEO audit report">

Here:

  • img identifies the image element.
  • src identifies the image file.
  • alt contains the image’s alternative text.

If you see an image like this:

<img src="website-audit.png">

the image does not have an ALT attribute.

Method 2: Use an Image ALT Tag Checker

For larger websites, manually checking every image can take a lot of time.

An image ALT tag checker can help identify images that:

  • Have missing ALT attributes
  • Contain empty ALT text
  • Have existing ALT descriptions
  • Need better descriptive text

You can use the IOT Global Agency Image ALT Tag Checker to check your webpage’s image ALT information:

Check Image ALT Tags with IOT Global Agency

This can make the process faster than inspecting every image individually.

What Does Missing ALT Text Look Like?

Consider this example:

<img src="digital-marketing.jpg">

There is no ALT attribute.

A better version would be:

<img src="digital-marketing.jpg" alt="Digital marketing strategy for a business website">

The second version provides meaningful information about the image.

How to Write Good ALT Text

Good ALT text should be descriptive, relevant, and natural.

For example:

Poor:

image

Better:

digital marketing dashboard

More descriptive:

Digital marketing performance dashboard showing website traffic and conversions

The appropriate length depends on the image and its purpose. The goal is not to write the longest possible description but to communicate the useful information clearly.

Google specifically recommends descriptive ALT text and warns against keyword stuffing.

Avoid Keyword Stuffing in ALT Text

One of the most common ALT text mistakes is repeatedly inserting keywords into image descriptions.

For example, avoid something like:

SEO agency SEO services SEO company SEO expert SEO marketing best SEO agency

This does not naturally describe the image.

Instead, write something relevant to what the image actually shows:

SEO audit dashboard showing website performance metrics

Your target keyword can be included when it naturally describes the image, but it should not be forced.

Should Every Image Have ALT Text?

Not necessarily.

Important images that communicate information should generally have useful alternative text.

Decorative images may use an empty ALT attribute:

<img src="decorative-line.svg" alt="">

The correct approach depends on the purpose of the image.

The goal is to make the page understandable and accessible rather than adding the same type of ALT text to every image.

Common Image ALT Tag Problems

When checking your website, look for these common problems:

Missing ALT Attribute

<img src="seo-image.jpg">

Empty ALT Attribute on an Important Image

<img src="seo-image.jpg" alt="">

An empty ALT attribute may be appropriate for a decorative image, but not for an important informational image.

Generic ALT Text

image

or

photo

This provides little useful information.

Keyword Stuffing

Avoid adding multiple variations of your keyword simply to manipulate search visibility.

ALT Text That Doesn’t Match the Image

The description should accurately represent what the image communicates.

ALT Text vs Image File Name

ALT text and image filenames are different, but both can provide context.

For example, this filename:

IMG12345.jpg

provides very little information.

A descriptive filename such as:

image-alt-tag-checker.jpg

is more meaningful.

Google recommends descriptive filenames as well as descriptive ALT text when optimizing images.

How to Check ALT Tags on a Website: Quick Checklist

Use this checklist when auditing your website:

  • Check whether important images have an ALT attribute.
  • Make sure ALT text accurately describes the image.
  • Remove unnecessary keyword stuffing.
  • Use descriptive language.
  • Keep decorative images appropriately marked.
  • Check product images, blog images, banners, and important graphics.
  • Make sure the ALT text makes sense in the context of the page.
  • Review images after uploading new content.
  • Use an automated ALT tag checker for larger websites.

How ALT Tags Fit Into Image SEO

ALT text is only one part of image optimization.

Google also recommends using standard HTML image elements, placing images near relevant content, using descriptive filenames, optimizing image quality and performance, and making images discoverable by search engines.

For example:

<img 
  src="image-alt-tag-checker.jpg" 
  alt="Image ALT tag checker analyzing webpage images">

This gives search engines and users additional context about the image.

Final Thoughts

Checking image ALT tags should be a regular part of your website SEO audit. Missing, generic, or poorly written ALT text can make your images less useful to both users and search engines.

Instead of manually checking every image, you can use an image ALT tag checker to quickly identify potential issues.

If you want to check your website’s image ALT attributes, try the IOT Global Agency Image ALT Tag Checker:

Check Your Image ALT Tags

Remember: the goal of ALT text isn’t to stuff keywords into images. The goal is to provide a clear, useful description that accurately explains the image and its purpose.