The 'decensored' tag implies the original image was Censored in its original version, but was decensored (drawn over the censorship) by a (for lack of a better word) decensorer. This is usually the case with Third-Party Edits of Game Assets that originally contained Mosaic Censoring.
All decensored posts should have the original as its parent. In addition, 'decensored' is different from both Nude Filter and Uncensored.