The new feature is twofold. First, attachments are now visible as previews at the bottom of a message. That means instead of just seeing a list of files with the option to click “preview” (which opens in a separate browser tab), you see a preview within the message itself. Clicking on the preview brings up a fullscreen view of the file, and you can navigate through several attachments the same way you flip through a photo slideshow.
Gmail users on iOS and Android have enjoyed for the attachment preview for quite some time, and it’s great to see the feature added to the desktop.
The more significant feature, however, is the ability to save an attachment directly to Google Drive. Simply click on the Google Drive icon that appears when you hover over an attachment and choose where to send your attachment.