Google Crawlers can’t automatically tell what is shown in an image. By giving your photos an alternative text, you can help google to ‘read’ them.
Alternative text as an image description
Alternative text (Alt Text) should describe what appears in the image using brief keywords. Feel free to use keywords which are also important on the rest of the page.
Since there’s something different to see in every image, each image should have its own Alt Text. If you don’t add an Alt Text, the file name will be used instead. Find out how to write alternative text for the different photo elements.
Avoid text in images
Google also can’t read text in images. Instead, it’s better to write short descriptions in the Alternative Text field. For more detailed texts, using a separate Text Element might be better.