This new feature is to address the issue of the 800 pixel limit which makes panorama images somewhat difficult to view.
To upload a larger sized panoramic photo there will be a 'Large Post' link next to all panoramic images in one's Manage section which are greater than a 2.5::1 ratio. Keep in mind that the limit is 400 kilobytes and may be no larger than 4000 pixels. The longest side must also be greater than 800 pixels. Only logged-in members may view these larger sized panoramic photos.
If anyone encounters problems or has suggestions on how this feature may be improved, please let me know. Thanks!