favicon in gatsby

 In gatsby.config.js, modify plugs.gatsby-plugin-sharp.options.icon

    {

      resolve: `gatsby-plugin-manifest`,

      options: {

        name: `gatsby-starter-default`,

        short_name: `starter`,

        start_url: `/`,

        background_color: `#663399`,

        theme_color: `#663399`,

        display: `minimal-ui`,

        icon: `src/images/favicon.svg`, // This path is relative to the root of the site.

      },