Abstract: According to the invented method, web pages are rendered on virtual PC's using different combinations of operating systems and browsers. Rendered web pages are stored as digital color images. For each picture a specific set of features are calculated and compared against the feature of a baseline image. Regions containing differences are marked and stored. Detected differences are displayed as transparent windows on top of browser under test. Transparent windows are sections of baseline browser images. These sections comprise regions where feature error threshold has been exceeded.