Does google index alt tags
Images are prevalent on the web and used to decorate and add information to pages. Alt tags are section of images that we have the ability to place some text explaining what the image represents. They are especially important for accessibility reasons. If for any reasons a user cannot see the image or have images disabled, the alt tag is used to explain to the user what the image is.
From experience writing blogs for our website, We have discovered that google definitely indexes alt tags. Many of our images have been indexed by google and come up in image search results. We have also had text from alt images indexed in the normal search results.
We have found that if your page is written well the alt text is rarely indexed. Google tries to understand what your page is about and only needs to look at the image tags if needed. The better your page is written the less the need is to closely review all aspects of it. What this basically means is there is a sliding algorithm in which content and many other parts come first and the alt text is much less important. But if your page is poorly written and google is having trouble finding what your page is about, it will also use the alt text to work it out.