Image Alt Tags

What are image alt tags?

Alt text is text which describes an image and improves accessibility for people who can’t see images on web pages, including website visitors who use screen readers. Search engines such as Google use image alt text alongside algorithms and the contents of the page to understand the content of the image.

An Example


Results can become relevant by adding some content and text around the image. You can aid in the discovery process by making sure that your images and your site are optimised for Google’s image algorithm. It’s important to always follow Google’s guidelines.

Google’s image best practices can be found here:

“alt attributes should be used to describe the image.”

If you have an image of rare whisky you should use the alt tag = “rare whisky”” (the keyword which best describes it.)

The title attribute should contain information about what will happen when you click on the image.

HTML Attributes

Below is an example of a full HTML image tag:

<img src=“imageofwebsite.jpg” alt=“SEO Company” title=“image tooltip”>

The alt and title attributes of an image are usually referred to as alt tag or alt text and the image title tag. Alt text provides a description of what the content of the image is and the function of the image on the page. So if you are using an image as a button to buy a SEO Audit, the alt text should say: “buy SEO Audit button”


The image alt tag is used by screen readers, which are browsers used by blind and visually impaired people, to inform them what the image contains. The title attribute is shown as a tooltip when you hover over the element, so in the case of an image button, the image title could contain an extra call-to-action, like “Buy a SEO audit for £199”, although this is not the recommended approach.

Each image should have alt text associated with it, not just for your SEO strategy but also because blind and visually impaired people won’t understand what the image is about.

Image Alt Tag Best Practices

Image alt text should be relevant and specific, but also representative of the topic of the webpage it’s on. You can use both the image’s subject and context to guide you.

It’s best to keep the image alt tag length to 125 characters.

Screen-reading tools typically stop reading alt text at this point, truncating long-winded alt text is not user friendly.

Keywords can be used within the image alt attribute. You can include your article’s main keyword as long as it is descriptive of the image. Additionally, you can use semantic keywords, or the most relevant search terms within a longtail keyword. For example, if your article’s main keyword is “SEO Services UK,” you might use “SEO” in your alt text, since “services” may not fit naturally.

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