The present invention provides an image processor and an image processing method wherein a specific image such as an image of which the printing is prohibited can be recognized at high speed and in addition, with high precision. A rendering command analysis unit passes a rendering object to any of a recognition unit for a raster image, a recognition unit for graphics and a recognition unit for a character according to the type of the rendering object in the rendering command and tries to recognize a specific image. The result of recognition by each recognition unit is passed to a recognition determination unit and it is synthetically determined based upon these results of recognition whether the specific image exists or not. Even if the specific image is formed by dividing into plural types of rendering objects, the specific image can be recognized by such recognition processing. Also, processing for generating output image data by an output image data generation unit according to a rendering command and outputting it is executed in parallel with such recognition processing so as to speed up processing.