Easily set the image_src link in the head of your document so that social networking sites like Facebook will know what image to use for thumbnails.
When a link is shared on Facebook and possibly other websites, the page is requested and scraped to find a thumbnail image to display in your post. When manually shared, the person sharing the link may choose from a list of images that were found on the page. However, when automatically shared, the first image found is used by default. This image is not always the image you may wish to be set as the thumbnail for the post. That's where the Page Image web part comes into play.
The Page Image web part will render a link element in the header of your page with your specified image. This link element is recognized by Facebook as the image you wish to have used as the thumbnail when sharing a link to this page. Since you will have control over this image, you will be able to ensure that the thumbnail used on Facebook is relevant to the subject matter on the page, and possibly gain more attention from your target audience.
The Page Image web part allows you to configure the image url that is rendered using the following 3 methods:
Page Image: This setting allows you to simply select the image you wish to use.
Attachment Guid: This setting allows you to specify an attachment using a macro expression. i.e. to display the teaser image of a Page (MenuItem) document type.
Page Image Url: This setting allows you to specify an absolute url either directly, or by using a macro expression.