The "alt" attribute is also important for accessibility and SEO as it helps assistive technologies to understand the contents of the image and it also helps search engines to understand the context and purpose of the image. When the search engines find that the alt tag is empty or missing, it could affect the ranking of your webpage.
It's a best practice to always include the "alt" attribute in your <img> tags and provide a meaningful and concise description of the image.
Social Plugin