Right-click: Open in new tab by cs8425

A context menu to open image/video/audio/frame in a new tab based on the add-on: "Open image in a new tab" by Didier Lafleur <a rel="nofollow" href="https://addons.mozilla.org/zh-TW/firefox/addon/open-image-in-a-new-tab/">https://addons.mozilla.org/zh-TW/firefox/addon/open-image-in-a-new-tab/</a>