Alt Text for SEO: A Beginner’s Guide to Optimizing Images

Alt text is an important part of image optimization for on-page SEO. This guide will teach you exactly how to use alt text to optimize all your images.
Tommy Griffth
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Jun 27, 2023
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4 min. read
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Today, we’re going to talk about image alt text optimization (or image alt tag optimization, or alt text for SEO, what some would call “image SEO”).

This is the process of optimizing all your images so that search engines understand them (as well as helping people with accessibility issues to better understand what the images are about).

In this blog, I’ll go through the exact step-by-step process and best practices that you need to follow when optimizing all of your images in an SEO-friendly way that’s also helpful for users.

Let’s get going.


First, let’s zoom out a little bit and really get the context of what we’re talking about. We’re talking about a search engine optimization component—and keep in mind that SEO is only one piece of digital marketing.

Using alt attributes is an image alt text for SEO strategy that will help your page rank on Google image search results. However, there are a lot of other things you can be doing in order to drive traffic and customers to your website.

Even more, within SEO, image alt text optimization is only one ranking factor of the entire on-page optimization process. So just getting this right, or just getting this wrong, is not going to make or break you either way.

To get a bigger picture of SEO and how to run a comprehensive audit, check out our alt tags SEO checklist.

Let’s move on to image alt text (or alternative text) and image title and file name now.

Robots vs Humans

Search engines are not humans, right? They do not view or see images the way that we do.

We, as SEOs and digital marketers, have to do something to help search engines a little bit (give them some hints on what images are about.)

One way we help search engines “see” images is by naming them properly with image filenames and alt text. These function as an image description that helps crawlers “see” the pictures on your site.

Furthermore, this is also used for accessibility: visually impaired or blind users use special browsers that read images to them, and alt text for images and images title can be helpful for that.

When you’re writing your alt text, you should generally stay within the 125-character count. Thus, you can populate that as much as you’d like, as long as it’s reasonable.

It’s important not to forget about the filename (this happens a lot, believe me). A lot of people upload a file with a very general name (e.g. “home-page-graphic-6.png”)—and that’s not good. You can (and should) be much more descriptive than that – both for screen reader users and for search engines as well.


This tactic is prone to over-optimization. I know this because I used to do it.

When people first get into search engine optimization, they get very excited about this. They go through the entire checklist and they say “OK, there are all the things I need to do to rank higher in Google, I’m excited about this.”

Eventually, they get to the image optimization part and they look at their images, and then they just…overdo it.

They stuff the image optimization with too many keywords (aka Keyword stuffing) and they just end up with a non-descriptive alt text which is an example of bad alt text. You should try to avoid making this mistake. Use relevant target keywords for alt descriptions and try not to overdo them.


Let’s look at a couple of examples.

Below, you will see an image from Zappos. The file name is “mens-boat-shoe.jpeg”. Remember, whenever you have spaces in your filenames, you want to use hyphensnot underscores.

As for the alt text (also known as “alt tag”), that is “Mens Boat Shoe”. That’s okay, it’s kind of a standard image and alt tag optimization. It could be a little better, but it could be worse as well. I think this is fine for all intents and purposes.

The image above includes an example of what the actual HTML code looks like (<img src=”image source link” alt = “alt text of your choice”>). Within the image tags, you will see both the file name and the alt tags.

Let’s look at an example of a “bad, better, best” situation.

Below, we have the image of a woman. A redheaded woman. She’s younger. She’s on a phone.

  • A Bad Alt Text example here would be “image source = woman.png”. The file name is “woman”, the alt tag is “woman”. It’s better than missing alt text in terms of optimization, but not that good. It’s just not descriptive enough.
  • better Alt Text example would be “woman-phone.png” as the filename, and the alt tag “woman using a phone”. These are good alt text and filename (much better than the example above), but they can still be improved.
  • The best example would be a file name called “red-hair-millennial-woman-iPhone10-iPhoneX.png” and the alt tag “redhead millennial woman using an iPhone10”. It’s much more descriptive alt text and there are a lot of types of phrases in there.

If you want to check how descriptive your alt tag is, say it out loud with your eyes closed (or just have a friend read it out loud to you). Visualize what you are saying and then see how close that visualization is to your actual image.

If you can be descriptive about it, if you get close, you’re in good shape.

Using the bad example, “woman”, if I just say that to you, you will imagine a…woman (probably very far from what the image is about).

That’s it, that’s all there is to image alt text and how to optimize your webpage with an image alt tag. The rule of thumb here is to be descriptive in both your file name and your alternate text. It’s great for search engines, but keep in mind that it’s just one component affecting your ranking on SERPs. It’s also very helpful from a web accessibility perspective, for visually impaired and blind users.

In Conclusion

If you’re JUST getting started with digital marketing, use our Internet marketing tutorial/ guide and our search engine optimization tutorial/ guide for a high-level overview of how they work.


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