disclosed herein are databases that contain image context categorizations , those categorizations identifying the context of an image based on a computed fingerprint . also disclosed herein are applications of such a database , including a viewing application that blocks the rendering of images with undesirable content noted by a content categorization , and a scanning application that locates images in a corpus or repository of images having certain content noted by content categorization , such as unlawful images . such blocking may be through an obfuscation technique , such as blurring , distorting an image , or may be through a replacement of image material . a categorization tool may include obfuscation with an aperture tool for clarifying portions of blocked images . detailed information on various example embodiments of the inventions are provided in the detailed description below , and the inventions are defined by the appended claims .