Alt text’s primary job is accessibility, and its SEO role is real but minor: it helps mainly in image search and gives a small amount of page context, not a meaningful lever on your page’s web ranking. So the honest split is that you write alt text first for the people using screen readers and for the cases where an image fails to load, and you treat its ranking effect as a modest bonus that lands mostly in Google Images rather than on the page itself.
Right-sizing matters because the keyword-stuffing reflex misreads the factor entirely. Alt text describes an image to someone who cannot see it, and that description is also one of the clearest signals Google has for understanding what an image depicts. That understanding feeds image search, where good alt text genuinely helps you surface. It also contributes a thin slice of context about the page’s topic, which is why it is not zero for web ranking. But it is a small signal among many, and cramming keywords into it does not push the page up the results. It degrades the experience for the users it exists to serve and can read as manipulation.
Calibrated properly, the factor sits where it belongs: a strong accessibility requirement, a useful image-search signal, and a minor page-context contribution. Treating it as a primary ranking tool overstates it; treating it as pure compliance with no SEO value understates it. The accurate position is accessibility-first with a modest, image-search-weighted SEO benefit.
When you write alt text, describe what the image actually shows, plainly enough that someone who cannot see it understands the picture and its purpose on the page. Let a relevant keyword appear only where it fits the honest description, never forced in for ranking. Do that across your images and you serve users, improve your image-search visibility, and capture the small page-context benefit without overinvesting in a factor that was never going to move your page rank on its own.