After changing your social share image, LinkedIn and Facebook will sometimes continue to show old cached content up to 7 days after changing the image. These platforms need some time to recache your job URL and show your newly uploaded image. The good news is that you can speed up this process yourself.
Debug the job URL via LinkedIn or Facebook
You can manually add the URL of your job post to the LinkedIn Debugger or Facebook Debugger to renew the information they've stored for that link. Just follow the steps on the respective debugger pages.