Google can’t read images. When you upload an image to your website via your CMS (content management system, such as WordPress), you have the option of assigning an Alt tag. Alt refers to the “text alternative” of an image. The alt tag tells Google what the image is about. This helps Google to confirm that the image is relevant to the page and therefore that the page is even more relevant to the terms it targets; it also helps Google to index your images and display them in Google image search results.
Alt tags
About the Author: Nicolas Laustriat

I am a CESI graduate, designer and multimedia integrator. I worked as a freelancer for a long time at the beginning of 2000, before joining EQUANCY, a strategic marketing and communication consultancy, where I deployed LAFARGE's new online communication strategy in 2003. Having become independent again in 2006, my expertise attracted attention and in 2009, in addition to my work as a digital consultant, I joined CEGOS as a trainer on the web project management, e-reputation and SEO modules. In 2010, I joined INHESJ (Institut National des Hautes Etudes de la Sécurité et la Justice) to present the evolution of online influence practices to large international companies. I assist major accounts in their excellent use of the Internet (best practices, sharing and deployment, crisis management, etc.), as well as business leaders and brands concerned with monitoring (and maintaining) their e-reputation, and communication agencies (white label). Testimonials from my clients: https://www.business-ereputation.com/avis-clients/