Alt Text
Alt text is a short written description of an image, set in the HTML alt attribute, that screen readers announce to visually impaired users and that search engines read to understand what a picture shows and when to surface it in image search.
Product images need alt text because a search engine cannot see a photo; it can only read the description you attach to it. The alt attribute does three jobs at once: it is read aloud by screen readers, it shows in place of an image that fails to load, and it gives crawlers a plain-language account of what the picture contains. Good alt text states what is actually in the frame, for example the product name, colour, material, and any text printed on the item, rather than stuffing keywords or repeating one phrase across every image. If an image is purely decorative, such as a background texture or a divider, an empty alt attribute (alt="") is correct so assistive tools skip it instead of announcing noise.
Consider a Shopify store selling handmade ceramics. A listing for a stoneware mug carries five photos: the mug face on, a close detail of the glaze, the handle, a size comparison next to a hand, and a lifestyle shot on a breakfast table. Generic alt text like "mug" or "product image 1" tells nobody anything. Written properly, the detail shot reads "close-up of speckled blue reactive glaze on a stoneware mug", and the size shot reads "stoneware mug held in one hand to show its 350ml capacity". A shopper using a screen reader now understands the range. Google Images has enough to surface the mug for someone searching reactive glaze mugs, and the merchandiser has captured the specifics that the photo was carrying silently.
The honest caveat is that alt text describes an image; it is not a place to hide content you want ranked. Specifications, dimensions, ingredient lists, care instructions, and customer reviews must exist as real, selectable text on the page. When that detail is baked into an image or an infographic instead, search engines and AI answer tools cannot read it, so the product looks thinner than it is and loses out to a competitor whose details sit in plain text.
This matters more as buyers ask AI assistants to shop for them. When someone asks ChatGPT, Perplexity, or Google AI Overviews for the best matte black kettle under a set budget, those systems work mostly from the text a page exposes. They lean on machine vision unevenly and cannot be relied on to read pictures the way a person does, so well-written alt text is one of the few signals that helps them attach meaning to your imagery and quote your product accurately. It will not carry a thin page on its own.
Treat alt text as one accessibility and discovery signal among many, not a ranking lever in isolation. It helps the right people and the right crawlers find an image, but the substance that earns the page its place still has to live in the visible copy.