Yes, but not the way most people think. It doesn't work by stuffing in keywords. Alt text describes what's actually in the photo, and search engines and AI tools use that description because they can't see the image the way a person can. A plumber installing a water heater needs alt text that says exactly that, not a list of services you offer.

Every photo that goes on a page people actually visit, yes. Full-size camera files are much bigger than a screen needs, and the smaller file loads faster for anyone checking your site on their phone in a driveway.

JPEG for real photos of jobs, your team, or your storefront. PNG for logos, icons, or anything with transparent background or sharp text. Most local business photos are JPEG. If your site builder or host offers WebP automatically, that's fine too, it's just a smaller version of the same idea.

Not directly through file size or alt text, since a stock photo can be optimized the same way a real one can. The real cost is trust and specificity. A generic stock photo can't be described as anything unique to your business, so it gives search engines and AI tools nothing to connect back to you specifically.

The filename is what the file is called before it's even uploaded, like tankless-water-heater-install-milford-ct.jpg. Alt text is a short sentence describing the image once it's on the page, for anyone using a screen reader and for search engines and AI tools reading the page. Both should describe the real photo, not just repeat your target keyword.

Most AI tools that summarize or recommend businesses read the text around and attached to an image, not the pixels themselves. That means your filename, alt text, and the surrounding page content are what tell an AI tool what's in the photo and why it matters. An unlabeled photo is invisible to that process even though a person can see it fine.