How can I update the Facebook thumbnail image for my Wix site?
The thumbnail image will appear when your site is shared on Facebook. The images give your visitors another way of identifying your brand.
To change your thumbnail image: From the left side of the Editor, click Settings > click Social Settings > click Upload Thumbnail > choose an existing image or click Upload Images > click Choose Icon.
According to Facebook's specification, the minimum dimensions for Thumbnail images are 200px*200px, and the maximum dimensions are 1500px*1500px. We recommend that you don't exceed 1000px*1000px.