I see this happen on the Chrome homepage. This is noted widely so don't let tutorials throw you here. You may have changed the default search to Bing so that shows PLUS those thumbnails as you visit sites.
If you want them to NEVER show you AFAIK you have to install an extension like:
Chrome keeps putting thumbnails on my bing.com homepage. Yes, I can X them off, but they reappear after I have gone to various websites. I see nothing in the chrome Extensions that will stop them and have found no help searching online. I do not want them captured and put on that page. Thanks for any help.