Whenever a new tab is opened in Google Chrome, it displays frequently visited pages as thumbnails under Most visited section . This is a useful feature to quickly launch your favorite sites. But for some reason if you want to remove any of the thumbnails then you can follow the below mentioned steps.
Remove Thumbnails from Most Viewed Page
Launch a new tab in Google tab either by pressing Ctrl + T or File menu -> New Tab. Then navigate to the thumbnail that needs to be removed and click the the X mark that appears while hovering over the thumbnail.
This would remove the thumbnail from the most viewed pages.
Restore Removed Thumbnails
If you want to get back any deleted thumbnails in Google Chrome then click the Restore All option available at the top the most viewed page.