Image alt text or alternative text describes the appearance of an image and can help search engines and visually impaired web users using screen readers to understand the content and context of an image.

There is some confusion around whether alt text can help to improve your rankings and whether or not it is worth spending time on. In this article, we’ll outline exactly how alt text works, whether or not it is an SEO ranking factor, and whether or not it is worth your time in 2025.

Is image alt text an SEO ranking factor?

Image alt text is an image ranking factor, not an on-page SEO ranking factor. Optimising image alt text can help your image appear higher in the image results, but it does not directly influence how your page ranks in Google.

Here’s what Google’s Search Central Advanced SEO document says about image alt text and SEO rankings:

“Google uses alt text along with computer vision algorithms and the page’s contents to understand the image’s subject matter.”

In the same document, Google also suggests:

“Alt text in images is useful as anchor text if you decide to use an image as a link.”

Where alt text can help you to rank

As we mentioned, alt text is not an SEO ranking factor. It does not have a direct impact on how your web page ranks in the organic search results. However, that doesn’t mean that you cannot generate traffic to your website through image search. Below is an example of two places where alt text can help your images to appear in the SERPs and one example of where it cannot.

Here’s where alt text can help your image to rank

Image that shows where alt text can help you to rank in Google
A second Image that shows where alt text can help you to rank in Google

Where alt text won’t help your page to rank

Image shows where alt text cannot help you rank in Google

How to optimise your image alt text for Image search

We recommend writing image alt text like you would write it if you were describing that image to another person.

Alt text aims to provide Google’s algorithm with “hints” about what the image contains. Descriptive text that provides a concise and accurate description of the image can help to improve how that image ranks in the Google image search results

As we mentioned above, Google has previously confirmed that alt text is not a direct on-page ranking factor; however, as far as SEO best practices go, you should always take the time to label your images with descriptive alt text.

Let’s take this image as an example and give you three examples of Bad, Good, Better, and Best Alt Texts that you could use:

Bad, Good, Better, and Best Alt Tag Examples

Bad Alt Text

“Image”

Provides no context to search engines around what the image contains

Good Alt Text

“Dog”

Provides some (limited) context to search engines around the content of the image

Better Alt Text

“Sitting Dog”

It provides good context for search engines to understand the content in the image and how it fits into the page. Whilst the alt text of “sitting dog” is a good indicator for search engines, it lacks specificity.

Best Alt Text

“Brown and White Border Collie Sitting”

This is the best alt text, as it provides specific information about the dog’s colour, breed, and actions featured in the image. This helps Google classify, display, and rank images according to their content.

Final thoughts

When it comes to SEO, there is no silver bullet or single ranking factor. SEO is a culmination of hundreds (thousands) of signals sent to search engines. While we know that image alt text is not a direct on-page ranking factor, we strongly believe that optimising image alt tags for search is a worthwhile endeavour that should be part of your on-page strategy.

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