Google reverse search phrase--where does it come from?

Question

I am using Google Chrome, and I use the Google reverse search engine, by right-clicking on the image and choosing the "Search Google for this image".

For some images that you have used with this reverse image search feature, there is a text phrase shows up in the text box next to the image like this (inside the red rectangle in the image).

I've checked the image's meta data, but there were no similarities, and I've also checked the images alt property in the html code, but there were no similarities either.

Where does this text come from?

Answer 1

I expect that it comes from Google's algorithm. Their facial and other image recognition has become quite good. I'm sure that some images are so common that they've been able to build a database of images with short descriptions. Not strictly necessary, but useful for finding text that describes images.

For a definitive answer you'd probably need to get a Google engineer in here.

Here's a post from Search Engine Land describing the mechanics of Google's image search which says, in part:

...Google analyzes the image, creating a mathematical model based on shapes, lines, proportions, colors and other elements. It then matches the model against images already in Google’s index. Google then does page analysis to take a text-based guess at what the image is...

Google also says:

Search by Image returns the best results for images that have related content already on the web, so you're more likely to get relevant results for distinctive landmarks or paintings than you will for more unique photos like your toddler's latest finger painting.