SEO

Writing alt text that helps shoppers and search engines

Plus a technical detail most free audits get wrong when counting.

2 min read
Diagram contrasting an image with no alt attribute, whose file name a screen reader announces, with an image carrying an empty alt, which it correctly skips.

The alt attribute is read aloud by screen readers, and displayed when an image fails to load. That is its primary function. Search engines using it too is a consequence, not the goal.

That hierarchy is not a moral stance, it is operational: alt text written for a human naturally contains the right words. Alt text written for a robot reads as spam, and Google treats it that way.

Three examples

QualityAlt text
UselessIMG_4471.jpg
Spamleather shoe men cheap shoe quality shoe buy shoe
GoodBrown leather lace-up boot, three quarter view on white background

The third describes what you would see. It carries material, colour, product type and camera angle, without repeating a keyword once too often.

The nuance most audits miss

There is an important difference between an image with no alt attribute and one carrying alt="", an empty attribute.

  • alt missing: screen readers often announce the file name, which is useless and noisy. That is a genuine defect.
  • alt="": this is the WCAG recommended way to mark a purely decorative image so screen readers skip it. That is a correct choice.
Adding the two together inflates the count. A tool announcing ninety images with no alt may be counting thirty-seven real absences and fifty-four perfectly legitimate empty attributes. Always ask for the breakdown before concluding.

Checking your own store

The most reliable alt text is not the one in the page HTML, where the theme can replace it with an empty attribute. It is the media property as stored in Shopify: open the product, click an image, and read its alt text in the admin.

That is the value you entered once, which no theme can misreport on your behalf. An audit that gives you a number without looking there, only at rendered HTML, is measuring your theme's work, not yours.

PixelUnik generates these descriptions with AI from the image itself. In the per-image editor you review and approve before anything is written to your store. In bulk processing the write is automatic, so review a sample before running a large batch.

Measure your own images

The free audit reads your store and gives you the real weight of your product images, with nothing to install.

Run the free audit See PixelUnik on the Shopify App Store

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