A method and apparatus are disclosed for testing the accuracy of digital test images generated by a computer graphics program executed on a computer graphics system. A test program is utilized to compare the test image with a reference image. The user defines regions of interest and a maximum error for each region. This allows the user to focus on a particular object or group of objects. Global image quantification verification generates one measurement of error or image difference for each region of the test image. Each region is divided into sub-regions and an average color value is calculated for each sub-region and the corresponding sub-region in the reference image. The differences between the averages for corresponding sub-regions in the test and reference images are calculated. A test image region may be unacceptably different from a reference image if a normalized sum of the absolute differences exceeds the maximum error.