Wondered why images never displayed on Gmail or you had to add senders to safe list before allowing images to display, that was security features by Gmail.
Gmail now allows images to be displayed in your messages across desktop, laptop, iOS and Android. Earlier images would be loaded from external servers, now Gmail hosts images on its own proxy servers.
Which means your images are safe and secure and are checked for viruses and malware and you don’t need to press “display images below” link. With this, your email is safer, faster and more beautiful.
Those who prefer to authorize image display on a per message basis can choose the option “Ask before displaying external images” under the General tab in Settings. Option will also be default for users who previously selected “Ask before displaying external content”
The new improvement will be rolled out today for desktop and for Gmail mobile apps in early 2014.