This change improves privacy, but you can remove them as well.
So you no longer see images in these thumbnails but are little icons or symbols. Update: From Chrome version 69, the thumbnails have become icons that represent the website. Google Chrome is one of the most used browsers in recent times because offers you a series of functionalities focused on optimizing the user experience and one of them is the possibility of accessing most visited sites quickly using thumbnails every time you open a new tab in Google Chrome.
