Google has announced an update to Gmail today which allows users to preview attachments and save them directly to Google Drive.
From today all emails with attachments feature a preview thumbnail. Hover over the thumbnail to download or save the file to Google Drive, or click on it to open a preview, which also offers the option to download or save the file.
File preview in Gmail.
Files in Google Drive can also be emailed as an attachment with one click — just open the file in Google Drive Viewer and click on the ‘email as attachment’ option in the File menu.