The development team at Gmail have shown off their newest innovation in image displaying technology this week: showing all images right off the bat. While this bit of technology might not seem all that innovative for the uninitiated, those that've used Gmail over the past several years have seen the "Images are not displayed" message more than once. This update allows them to be displayed without the possibility of malicious bits and pieces appearing.
When Gmail originally stopped showing all images, it was because the images being shown were hosted be servers Google didn't control. With this update, they've initiated a service which serves all images through Google's own secure proxy servers. This means that they're checked and cross-checked before you see them.
Of course you'll still be able to see odd images and the random not-safe-for-work image, but you'll just have to live with it. Unless you activate the "Ask before displaying external content" setting. To activate this, you'll have only to head to your settings gear, find the "General" tab, and click in. There you'll find the "Ask before displaying external content" toggle ready to be check-marked.
Google has suggested that this proxy server use is just the most recent of their continuing roll-out of security efforts for the Gmail universe. This feature will be activated for your desktop machine - through web browsers - as early as today. The app versions of Gmail will see instant viewing of images with proxy server use in early 2014.