Why alt text matters

Search robots do not see images — they read text. The alt attribute is the text equivalent of an
image, and the robot uses it to understand what the image contains. Without alt, photographs on a
page effectively do not exist as far as search is concerned.

The second function is accessibility. Screen readers announce the alt text when they reach an
image. WCAG, the web accessibility standard, requires meaningful alt attributes as a level A
condition.

Alt text in e-commerce: how to write it

For product photographs a simple formula works:

<img src="product.jpg" alt="Nike Air Max 270 white running shoes size 44">

What to include:

  • The brand — when it matters to the buyer
  • The model name — exactly as it appears on the product page
  • The key attribute — colour, material or type, if that is what people search by

What to leave out:

  • The words image, photo or picture — the search engine knows that already
  • Technical file names — DSC00123.jpg carries no meaning
  • Keyword stuffing — buy cheap Nike shoes online now is spam

Decorative images: the empty alt

For backgrounds, dividers and icons that carry no information, the correct form is an empty
attribute:

<img src="divider.png" alt="">

That is an explicit signal to the screen reader that the image should not be announced. Omitting
alt entirely is an error: the screen reader will read out the file name instead.

Image search as a traffic channel

For e-commerce, image search is an underrated channel. People search for a blue sofa, Nike Air Max
trainers or a floral print dress, and land directly on product pages through the images. Alt text
is one of the main ranking factors in that channel, alongside the file name and the surrounding
text.

Tip: when generating product pages in bulk, fill alt automatically from a template such as
{Brand} {Model} {Key attribute}. Even a templated alt beats an empty one.