Images as a Ranking Surface
Start with the ranking side. Google Images remains one of the largest search surfaces on the web, and product, how-to, and local queries routinely show image packs in the main results. An image can only rank if Google understands it: a descriptive file name (kitchen-remodel-phoenix.webp, not IMG_4032.jpg), alt text that says what's actually in the picture, and surrounding text that gives it context. Image sitemaps and structured data extend that further for product and recipe-style content.
Alt Text: Accessibility First
Alt text does double duty, and this is where most sites quietly fail. WebAIM's annual survey of the top million home pages consistently finds missing alternative text among the most common accessibility failures on the web. Alt text exists first for screen-reader users; it should describe the image's content and function, not stuff keywords. “Technician replacing a furnace filter” serves a blind visitor and the crawler; “HVAC repair Phoenix best HVAC company” serves neither.
Images and Core Web Vitals
Then there's speed, where images dominate. The Largest Contentful Paint element, the thing Core Web Vitals actually measures, is an image on the large majority of pages, which is why oversized hero images are the most common single cause of a failing LCP score. The fixes are mechanical: serve modern formats (WebP or AVIF cut file size 25–50% versus JPEG), size images to their actual display dimensions, compress them, and set explicit width and height attributes so the browser reserves space and the layout never shifts.
Images aren't decoration. Chosen and optimized with intent, they're one of the few elements that support rankings, accessibility, and conversion at the same time.
Loading strategy matters as much as file size. Anything below the fold should carry loading="lazy" so it never competes with the content a visitor actually sees first; the hero image should do the opposite; load eagerly, and ideally get a preload hint so the browser fetches it before it finishes parsing the page. Getting this backwards (lazy-loading the hero) is a classic self-inflicted LCP failure.
AI Search Reads Images Too
AI search adds a newer reason to care. Multimodal engines read images alongside text, and answer engines increasingly pull illustrated steps and product shots into their responses. The same signals that help Google Images, descriptive alt text, contextual captions, structured data, are what make your images legible to AI systems deciding what to show.
A Practical Image Audit
A practical audit takes an afternoon: run your key pages through PageSpeed Insights and note which LCP elements are images, convert heroes to WebP/AVIF at display size, write real alt text for every meaningful image (decorative ones get empty alt attributes, alt=""), add lazy loading below the fold, and check that no image lacks width and height.
NYFTY Labs folds this into every build and audit we run, image weight is usually the fastest Core Web Vitals win available, and alt-text coverage is one of the cheapest accessibility and SEO fixes a site can make.
