Google is working on a tab preview feature for its Chrome browser, similar to what was present in Opera back in 2010, and which Microsoft also added to its Edge browser in 2015. The new UI elements are called Tab Hover Cards and they'll replace the classic tooltips that show up when you place your cursor over a tab.
As reported by Windows Latest, the latest Chrome Canary builds have a couple of new flags relating to this new feature. One enables the Tab Hover Cards themselves, which provide information about the tab, such as the title of the page and the URL. Image previews, however, are part of a separate flag, so you can choose your preferred style of preview.
Tab Hover Cards are available for the Windows, macOS, Linux, and Chrome OS versions of the browser. Image previews, despite being available as a flag, haven't actually been implemented yet, so you can't actually try them yet. It's not currently clear when the feature will be available for the general public, but it should happen in the coming months as it makes its way through the testing cycle.
If you want to try it out right now, you can download Chrome Canary here, though you should be aware that experimental builds are likely to be very unstable. As a bonus, the latest builds also finally include a dark mode that respects the system-wide dark theme in Windows 10.
Source: Windows Latest