This article explains how to preview Gmail attachments without leaving a message. Instructions apply to most current web browsers.
You can preview most file attachments, including images, audio files, PDFs, and video clips, without taking up space on your computer. This feature is useful if there are attachments that you don't need to save. For example, if someone sends you a Word document that you need to read, you can preview it right there and then respond to the email without downloading the file.
Email attachments are also easily integrated into Google Drive. If you don’t want the attachment to take up space on your hard drive, save it to your Google account. This feature allows you to delete the email, but view the attachment again whenever and wherever you want.
Open the message containing the attachment you want to view.