Image Alt Text

What Is Alt Text and Why Does It Matter?

Alt text (short for "alternative text") is the text description attached to an image via the HTML alt attribute. When an image fails to load, alt text appears in its place. Screen readers read it aloud for visually impaired users. Search engines use it to understand what an image depicts.

<img src="golden-retriever-puppy.jpg" alt="A golden retriever puppy sleeping on a blue blanket" />

It's one of the simplest things you can add to a webpage, and one of the most consistently neglected.

Why Alt Text Matters for Real People

Accessibility: Approximately 2.2 billion people worldwide have some form of vision impairment. Screen readers like JAWS or NVDA announce alt text when they encounter an image. Without it, a user hears either nothing, or the filename (img_20240901_082311.jpg) — which tells them absolutely nothing.

Poor alt text doesn't just inconvenience — it actively excludes. For e-commerce sites, a product with no alt text means a visually impaired customer simply cannot know what they're buying.

Images failing to load: Slow connections, CDN outages, browser extensions that block certain domains — images fail to load more often than you'd think. Alt text fills the gap.

SEO: Google can analyze images through AI, but alt text remains the clearest and most reliable signal about what an image contains. Good alt text, particularly for product images, can send traffic from Google Image Search.

How to Write Good Alt Text

Be specific and descriptive. Describe what's actually in the image, not what you wish was there.

• ❌ "Dog"
• ✅ "A golden retriever puppy sleeping on a blue fleece blanket"

Context matters. The same image might need different alt text depending on why it's on the page. A photo of a bowl of pasta on a recipes site: "Homemade spaghetti carbonara with crispy pancetta and fresh parsley". The same photo on a cookware site showing off a pot: "Penne pasta served in a stainless steel saucepan".

Don't start with "Image of" or "Picture of." Screen readers already announce that they've encountered an image. Starting with "Image of..." is redundant.

• ❌ "Image of a laptop on a desk"
• ✅ "Open MacBook Pro on a wooden desk with code editor on screen"

Keep it under 125 characters. Screen readers often truncate at this point. The core description should come first.

Don't stuff keywords. Alt text is not the place for keyword repetition...