Ability to view image links at their full size

[ablake]

Many reddit posts are image links. Currently, the app only displays thumbnails of images. It would be good to be able to view the full-size images.

• On the news item view for an image link, a high-resolution version of the image should be used that expands to fill the user's screen.
• Ideally, this image should be pinch-zoomable.
• Double-tapping the image should alternate between 100% zoom on the image and whatever zoom level fits it to the user's screen.
• When the image is zoomed, it should be both vertically and horizontally scrollable.