Google's John Mueller responded to questions around image SEO, specifically explaining that while the image itself and the alt text is useful, so is the page that image is embedded on. This is all useful for Google to know the relevance of an image based on a specific query.
John said when it comes to understanding the image, having a photo of a beach on a site is good and all, but it doesn't tell you much. If that photo is embedded on a hotel website, it means, that is the beach by that hotel. If it is embedded on a photographer's website, it tells you this photographer can take photos by the beach, and so on - you get the point.
A Reddit thread asked:
Are images alt texts still relevant for SEO with all the computer vision and images recognition advancement? Is there any info of Google or other search engines using machine learning models to crawl images rather than relying on the user provided alt texts?
Here is how John replied:
For image search, there's the context that comes from the page + image combination that matters. A photo of a beach might be a relaxing poster, it might be the beach from a hotel, it could be the site of a chemical spill. Just knowing that the image is of a beach doesn't really give sufficient background information to be able to show it in image search appropriately. A lot of it does come from the page, and the alt-text is unique in that it's what directly connects the image to the page with context.Unless your site is a photo agency, traffic for "photo of a beach" isn't going to be that useful - but for a hotel, having "hotel with beach in X" can be relevant. Again, a lot of that can come from the rest of the page, but the alt attribute value is a unique opportunity to give context. (And with that ... if you use AI to create alt texts based on the image file, and get "photo of a beach" as the alt text for that image, you're not getting the most out of the alt text, both for users & search engines.)
So yes, the page the image is embedded on is also important for many reasons.
Forum discussion at Reddit.
