8   A guide for Downloading the Columbia Pho- tographic Images and Photorealistic Computer Graphics Dataset The download and other additional information for the dataset is described in the dataset website, accessible from the Trustfoto website:  http://www. ee.columbia.edu/dvmm/trustfoto. Except for the Personal Columbia  set, we are not able to diseeminate the original images from the PRCG, Personal Greenspun, Google and Recaptured PRCG  image sets, due to copyright con- striants.  We have webpages for each of the image sets, which show the thumbnails from the image sets.  The  PRCG  and the  Google  thumbnail webpages provide the hyperlinks and the URLs to the original location of the images. Therefore, researchers can follow the URLs to access the origi- nal web pages containing the images and download the images if they want. The following list describes how to obtain the image sets of the Columbia Photographic Images and Photorealistic Computer Graphics Dataset. ²  PRCG  set: The PRCG  images can be downloaded by following the hyperlinks or the URLs listed in the  PRCG  thumbnails page, acces- sible from the dataset website.   The thumbnail page also contains meta-information including the source URL, the content category, the software or tools used, the rendering techniques, the geometric mod- eling techniques and the post-rendering processing. ²  Personal set: 1.  Personal Columbia  set: The Personal Columbia  images come in three versions: the downsized (about 700x500 pixels) JPEG ver- sion (55MB), the original-size (about 3000x2000 pixels) JPEG version (1GB), the original-size RAW-format version (4.9GB). The downsized version are used in our work for experiments [21]. The downsized and the original-size JPEG version of the  Per- sonal Columbia  set can be downloaded from the dataset website, while the original-size RAW-format version will be distributed in DVD and can be obtained upon request. The Personal Columbia thumbnail webpage shows the thumbnails of the Personal Columbia set as well as the meta-information of the images such asthe file- name, the lighting/object category, the photographer and the camera model. 20