Four-image montage comprising images taken by Rosetta's navigation camera on 2 October from a distance of 19 km from the centre of Comet 67P/Churyumov-Gerasimenko. The image scale is 1.45 metres/pixel, so each 1024 x 1024 pixel frame making up the montage is about 1.5 km square.
The individual image frames and more information is available via the blog: CometWatch – Focus on the 'neck'