Introduction to Alt Text
If you’ve spent any time adding images to websites, you’ve seen that little box labeled “alt text.” But what exactly is it? Alt text, short for “alternative text,” is a brief description you add to an image’s HTML code. This description shows up in place of the image if it can’t load, and it helps screen readers relay information about images to users who are blind or have low vision.
It might seem like a simple detail, but alt text matters. For lots of people, it’s the difference between understanding what’s on a page and having no clue what’s there. Good alt text isn’t just about following the rules—it’s about making information available to everyone.
Benefits of Using Alt Text
There are three core reasons why alt text deserves attention. The first is accessibility. People who use screen readers depend on alt text to interpret images. Without it, visual content vanishes for them. This can include diagrams, charts, buttons, and photos—pretty much anything besides regular text.
Next up is search engine optimization, or SEO. Search engines like Google use alt text to understand what’s in your images and how they relate to page content. So, if you describe images well, you’re giving your site a small but meaningful boost in search rankings.
Last, there’s the plain practical side. Sometimes, images just don’t load. Maybe the internet connection is spotty, or maybe there’s a technical hiccup. When that happens, alt text shows users what was supposed to be there, so they don’t miss out entirely.
Key Elements of Effective Alt Text
So, what makes good alt text? First, it’s descriptive and concise. You want to capture what the image shows, but don’t write a whole paragraph. For example, if you have a photo of a black dog jumping over a log, something like “black dog jumping over a fallen log” works much better than just “dog.”
Keywords matter, too, especially for SEO. If your page is about baking apple pies, and you have a photo of lattice-topped pie cooling on a windowsill, you might include “apple pie” in the alt text. Still, there’s a balance—throwing keywords everywhere helps no one.
That leads to another rule: don’t overdo it. “Keyword stuffing” is when someone jams as many keywords as possible into their alt text, thinking it will boost their search ranking. This usually backfires and could even get your page in trouble with search engines.
Best Practices for Crafting Alt Text
Here’s where things get a little more practical. When you’re writing alt text, start by asking: “What am I actually showing?” Try to imagine someone who can’t see the image at all. Is the image purely decorative, or does it add something useful to the content?
Let’s say you have an image that explains a key step in a recipe—maybe how to knead bread dough. A good description could be “hands kneading bread dough on a floured kitchen counter.” You don’t need to mention every detail, but you want someone to get the gist.
Consider why the image is there. Is it showing a specific product, illustrating a process, or creating a visual break? For purely decorative images—like lines, flourishes, or spacers—you can either give them empty alt attributes (`alt=””`) or skip the descriptive text, so screen readers don’t waste time on them.
When it comes to length, keep things short and direct. Most alt text should be under 125 characters. Short sentences are usually easier for screen readers and are more likely to be helpful for everyone.
Common Mistakes to Avoid
Some pitfalls crop up time and time again. The biggest mistake is simply leaving alt text blank on important images. That’s like putting up a blank sign in the middle of a busy road—no one knows what’s supposed to be there.
Another common error is adding “image of” or “picture of” to every description. If someone is using a screen reader, the tool will already announce that it’s an image. Writing “image of a sunset” just makes things longer than they need to be—“colorful sunset over mountains” works better.
And then there’s the temptation to cram way too much in. Some people want to include every pixel—“A photo showing two small dogs, one with a red collar and the other with a blue collar, sitting on a faded wooden deck next to a green potted plant and eating kibble from a silver bowl on a warm sunny day.” That’s too much. Try to focus on what’s important for the context.
Tools and Resources for Writing Alt Text
You don’t have to do all this guesswork on your own. There are plenty of tools out there to help make sure your images are accessible. Some of the better-known accessibility checkers include WAVE, axe, and Lighthouse. These tools can scan your site and flag images that are missing alt text or have descriptions that are too long or clumsy.
If you’re looking for a frame of reference, there are guides and templates available with sample alt text. Many web platforms, like WordPress, have built-in prompts or examples. When in doubt, following these models can save you time.
There are also browser extensions and AI-powered tools that offer recommendations for alt text. While I wouldn’t trust a robot to do all the work, they can be a handy starting point when you’re stuck on what to write.
Examples of Good and Bad Alt Text
It helps to look at some real-world examples. Imagine an image of a red bicycle leaning against a brick wall. Good alt text would say something like “red bicycle parked against a brick wall.” You’ve got a clear picture in your mind even if you can’t see the actual photo.
Bad alt text might read “image123.jpg” or simply “bike”—both are too vague. Worse, you might see something like “picture of a bike image red funny cool wall outside,” which is just a pile of words trying to game the system.
For more involved images, like charts or infographics, you might need a slightly longer description. For example, if you have a pie chart breaking down website traffic sources, you could use: “Pie chart showing 60% of traffic from search engines, 25% from social media, and 15% from referrals.” That hits the main point without getting lost in all the data labels.
It’s worth reviewing resources like accessibility guides or checking out examples on specialized web accessibility sites. Sometimes, it just takes a couple of good examples to get the hang of how much information is enough.
Conclusion
Alt text probably isn’t the most glamorous part of putting together a website. Still, it consistently proves its worth to real people—whether they’re browsing with a screen reader, stuck on a slow connection, or just trying to find something on Google.
If you make a habit of writing clear, context-aware alt text, you’re helping your site work better for everyone. It’s not about perfection. It’s about covering your bases and making sure nobody misses out.
Plenty of web pros check their images once a quarter, or whenever they update important pages. That’s a solid routine. Over time, the extra minutes you spend on alt text add up to a more inclusive and effective site for all your visitors. That’s just good business sense, and it’s easy to keep up once you get used to it.