This is a known issue and we have provided a quick solution for this.
The Facebook crawler has to see an image at least once before it can be rendered. This means that the first person who shares a piece of content won't see a rendered image. So we have to force a rescrape by using Facebook's 'Sharing Debugger'. We have provided a one-click solution for this in your admin panel (Click on 'Campaigns'--> Click on your campaign title --> Now click on the 'Facebook Sharing Debugger' button that appears on the top of the screen, next to the yellow shaded text message: 'If Facebook does not update the image, please click the following button'.
Check to ensure the image is appearing fine. If not please click on the button again or contact us.
Best of luck with your campaigns!
