London Telegraph 
Feb 27, 2013
Analysis of images by the Committee for Human Rights in North Korea indicates that the size of Camp No. 25 alone has increased 72 per cent and perimeter guard posts, which numbered 20 in 2003, had increased to 43 in 2010.
The camp is believed to house some 5,000 prisoners, in conditions that human rights groups have described as “deplorable.”
The detailed pictures, provided by DigitalGlobe, a US-based commercial satellite image company, also show the perimeter fence has been extended by around 4,600 feet, agricultural plots have been rearranged and a new gateway has been constructed.
Based on the images and information from defectors, the human rights group believes North Korea is being forced to expand its prison network for a number of reasons, one being the purges conducted by Kim Jong-un of senior members of his father’s administration out of concern that they pose a threat to his power base.