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Marques Coleman

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How to Write the Perfect Image Alt Tag

By SEOOne Comment

How to Write the Perfect Image Alt Tag

If you’re an SEO marketer, it might seem like new rules and recommendations are cropping up every now and then: optimize your headings, make your content keyword-rich, don’t make your content too keyword-rich… The advice on how to rank well is endless but it’s often conflicting and confusing. That’s why, instead of taking advice from someone with questionable authority and knowledge, you should just take a look at the facts and research and let that be the basis for your conclusions.

Today, we’re going to be talking about image alt tags – why and how you should write them, as well as how to optimize them to achieve the best possible results. The fact is that Google’s image search accounts for more than 22% of all Internet searches. There’s also the fact that 3% of all clicks from Google come from images.

Even without any other facts, these numbers speak volumes about why optimizing your image alt tags is important. Simply put, your images can bring you as much traffic as the rest of your content. Let’s have a look at why:

The Significance and Benefits of Writing Image Alt-Tags

The term “image alt-tag” is often used to describe the alt attribute within an image tag. In simple terms, alt-tags should describe what’s on the image. They are a way to present the visual on your website in a verbal way, which means that it will be processed by search engines.


  • Speaking the Language of Search Engines

Search engines don’t have any other tools to analyze the content of the images on websites (at least, not yet). For search engine algorithms, the only reference they have is the text that is in the HTML image tag, i.e. the title tag and alt-tag.


  • Better Accessibility

Users with visual disorders who use screen readers will experience the images on your website with the help of alt-tags.


  • Backup Plan

Alt-tags are automatically a mechanism that gets shown to users in case an image can’t properly load. In other words, it’s better to have your blog post-split by “image of a dog running” than “untitled 3”.

The Do’s of Writing Image Alt-Tags


  1. Short and Informative

When it comes to SEO, it might seem tempting to fill up the alt-tag area to the max to give your images the best chances to get discovered by search engines based on a different keyword. Well, it’s not exactly like that.

Firstly, if you include spammy, long alt-tags on your images, search engines might even consider this a black hat SEO technique and penalize you. Secondly and more importantly, a lengthy image alt-tag will have the opposite effect for the accessibility and loading that we have previously mentioned.

Only write what’s necessary to understand the core of the image. As soon as you capture this in a couple of words, you’re good; no need to go any further.


  • Relevant to the Content in Question

Relevancy is another super-important factor when it comes to writing SEO image alt tags. Alt-tags should not be seen as a space for unnecessary comments or remarks. Rather, all of the words included in the alt-tag should be relevant to the image.

Just imagine yourself as a user doing a Google search for “dog running”. After you click on Search, you don’t expect to see an image of Buddha meditating which is the very magic of Google and its core value. Google knows exactly what you’re looking for because it scores the relevancy of the image to its title tag and alt-tag and uses this score to rank results in image search.


  • Keyword-Driven Writing

If you pay a lot of attention to SEO on your website (which you definitely should), alt-tags are another important factor in the search engine optimization of your site which you should pay attention to.

Take a look at your primary keywords. Do the images on your site reflect those keywords, and are they mutual to each other? When you compare the first two factors that we talked about, having a website full of images that are not relevant to the keywords that you’re targeting will get you nowhere.

Example: you have a website where you’re writing about training a ferret (yes, those exist) but it’s full of images of dogs running with the alt-tags to match. Simply put, those running-dog images are just there as a decoration and do nothing to power your search engine rankings. As a result, you’ll be missing out on all that traffic coming from searchers of ferret images (yes, those exist).


  • Standardized, Approachable Vocabulary

“Dog running” is a good image alt-tag. “Canine in haste” is a bad image alt-tag.

Just like the rest of the content on your website, alt-tags should help understanding, and not hinder it. You should also keep non-native speakers in mind, who will usually use the simplest terms to do a search. Also, if you’re running a niche website, cater to lay people by using approachable vocabulary in your image alt-tags.

The Don’ts of Writing Image Alt-Tags


  1. Alt-Tags for the Sake of Alt-Tags

If you don’t have anything valuable to add to your image description, you don’t have to do it. You should avoid unnecessary alt-tags that add nothing of value to the website, post, or the image itself. This is often the case when an image transfers enough meaning on its own and adding more would just be over the top.


  • Overreliance on Keywords

Even though your image alt-tags remain hidden most of the time, you shouldn’t fill them up with keywords that don’t add any value to your content. Just like other sections of your website or blog, alt-tags should not be spammy or keyword-stuffed.


  • Copy/Paste Alt-Tags in Different Content

Just like with content and writing, copying alt-tags between different contents will be considered auto-plagiarism, and it’s unlikely that any of those images will rank well. Remember some of the features of good image alt tags that we have talked about. If you have 10 images for “dog running” on your website, is it possible that all of them are equally relevant to that tag?

Aim to always write unique, individual alt-tags, title tags and image descriptions for every image that you add to your website. Ideally, you would never have two identical image alt-tags, even if you choose to include very similar images.


  • Lack of Multilingual Alt-Tags

A big mistake some websites make with their image alt-tags is to forget to add multilingual tags for their international visitors. It’s an even bigger mistake if you already have a lot of non-English audience, but if you don’t, maybe this is the reason why.

Pay attention to adding multilingual alt-tags for international visitors. This can help you get discovered by people from all over the world. Also, it’s a great way to enter new markets with your content, even if you’re still planning on publishing content that’s just in English. Users will be able to find you through images and continue reading if your content is high-quality and relevant.

In Summary

Just like with all other elements in SEO, there are a lot of things to pay attention to when writing image alt-tags. Good image tags can launch your photos into search engine heaven, while poor ones can bury them deep down on the 10th page of Google’s image search.

The key takeaways from this short guide on how to write image alt text are:


  • keep them short
  • make them relevant, informative and valuable
  • don’t overstuff with keywords but do use target keywords sensibly
  • use everyday language; imagine yourself as the searcher who’s looking for exactly that
  • add multilingual alt-tags if you want to attract or retain an international audience

Share your ideas for the image above – what would be the example of a good and a bad alt-tag for this illustration?

Marques Coleman is a blog writer at TrustMyPaper, a research writing service. He specializes in marketing and copywriting. Moreover, he is an avid traveler and always tries to learn something new.