Why Alt Text Matters
Here's the thing about alt text — it's invisible to most people. But for anyone using a screen reader, it's the only way they experience your image. That's why it can't be vague or generic. "Photo" or "image1.jpg" tells them nothing. You're essentially writing a description that lets them understand what sighted people see instantly.
And it's not just for accessibility. Search engines can't "see" images either. Good alt text helps your images get found, which means better SEO and more people discovering your content. It's a win across the board.
The Basic Formula
You don't need to overcomplicate this. Start with a simple structure: describe what's in the image, keep it factual, and stop when you've covered the important parts.
Most alt text should be 125 characters or less. That's not a hard rule, but it keeps you focused on what matters. If you find yourself writing a paragraph, you're probably including too much detail.
Good Alt Text Example
"Woman in business attire presenting accessibility guidelines on a whiteboard to a small team in a modern office setting"
Not Helpful
"Meeting image" or "team discussing stuff"
Note: Individual learning outcomes vary from person to person. The techniques here work for most images, but your specific context might need adjustment. Test your alt text with actual users when possible.
What Changes by Image Type
Not all images need the same level of detail. A decorative icon gets a short description. A complex chart needs more information. A photo of people needs enough context that someone understands who they are and what's happening.
For photos:
Include who's in the image, what they're doing, and the setting if it matters. "Woman in a navy blazer presenting to colleagues in a conference room" tells the full story.
For charts or data:
Describe what the data shows. "Bar chart showing accessibility compliance rates across 12 government departments, with adoption ranging from 45% to 92%" gives the reader the actual information, not just that a chart exists.
For icons:
Keep it minimal. "Checkmark icon" or "accessibility symbol" is enough. Don't write "a green circle with a white check mark inside" — just describe what it represents.
Common Mistakes to Skip
Starting with "Image of"
Screens already say "image" — you're just adding extra words. Jump straight to the description.
Being Too Vague
"Team meeting" leaves out important details. Who's in the room? What are they discussing? Make it specific.
Stuffing Keywords
Alt text that reads like spam helps no one. Write naturally. Yes, keywords matter for SEO, but readers come first.
Duplicating Captions
If the image already has a caption below it, your alt text can be shorter. You're not repeating — you're complementing.
Testing What You've Written
The best way to know if your alt text works is to test it. If you can, try reading it out loud without looking at the image. Does it make sense? Does it give enough context? Or does it leave someone confused?
Better yet, share your page with someone who uses a screen reader. They'll tell you immediately if your alt text helps or if it's missing something. That real feedback beats any guideline.
Most importantly, don't leave images without alt text. An empty alt attribute is worse than short alt text. Even a simple description is infinitely better than nothing. And remember — you're not writing for Google or for algorithms. You're writing for actual people who deserve to understand what's on your page.
