Image alt text is one of the quietest wins in SEO. It helps Google understand your images, it is read aloud to people using screen readers, and it shows up when an image fails to load. Get it right across a whole site and you pick up accessibility compliance, better image search visibility, and a small but real on page relevance signal, all at once.
Here is exactly how we write image alt tags at TEJ, and the rules we apply to every website we build.
What is an image alt tag?
The alt attribute (short for “alternative text”) is a written description added to an image in the HTML, like this: <img src="hero.jpg" alt="A short description of the image">. Browsers show it if the image cannot load, search engines read it to understand what the image shows, and screen readers announce it aloud to people with visual impairments.
Why alt text actually matters
- Accessibility. Screen readers depend on alt text to describe images. It is also a requirement under WCAG and the European Accessibility Act for many sites.
- SEO. Google uses alt text, together with the surrounding content, to rank images in Google Images. That is a genuine and often overlooked source of traffic.
- Resilience. If an image 404s or a slow connection stalls, the alt text still tells the visitor what should be there.
- Relevance. Clear, descriptive alt text reinforces what the whole page is about.
How to write the perfect alt tag
1. Describe the image accurately and specifically
Say what is actually in the picture. “Woman using an Instagram AR filter on her phone” beats “image1” or “photo” every time. Aim for a natural phrase that lets someone picture the image without seeing it.
2. Keep it concise
Around 8 to 15 words is the sweet spot. Screen readers read the entire string aloud, so avoid rambling. If an image genuinely needs a long explanation, put that in the surrounding text or a caption instead.
3. Include your keyword only when it fits
If your target keyword honestly describes the image, work it in naturally. Never stuff keywords, because alt text crammed with search terms reads badly for real users and looks manipulative to Google.
4. Do not start with “image of” or “picture of”
Screen readers already announce the element as an image, so those words waste the listener’s time. Jump straight into the description.
5. Leave decorative images empty
Purely decorative images, like dividers, background flourishes and spacers, should use an empty alt attribute (alt="") so screen readers skip them. Do not remove the attribute entirely, just set it to empty.
6. Add context to functional images
If an image is also a link or a button, the alt text should describe the action or destination, such as “Contact TEJ” rather than “envelope icon”.
Good vs bad examples
- Bad:
alt="IMG_2043" - Bad:
alt="web design dublin web design ireland cheap websites" - Good:
alt="TEJ web designer reviewing a homepage layout on a laptop"
How to add alt text in WordPress
Open the Media Library, click an image, and fill in the Alt Text field. In the block editor or Elementor, select the image and add the alt text in the settings panel. Do it as you upload and it becomes a habit rather than a backlog to fix later.
The bottom line
Perfect alt text is simply an honest, concise description of an image, written for a human first, with your keyword included only when it genuinely fits. Apply that single rule to every image and your site becomes more accessible, more resilient, and easier for Google to understand.
Want a website that is built right from the ground up, with SEO and accessibility baked in? Talk to TEJ about web design.