If you’re testing your website to make sure it works properly for visitors, you’re off to a good start. However, many companies overlook the importance of visual testing — i.e., evaluating layout, images, text, design, and other visual components. As the number of browsers, devices, operating systems and screen sizes explode, teams need to be more cognizant of current and emerging issues in responsive design. These bugs may be a mild inconvenience for users, or they could be what prevents them from completing their purchase.
https://www.mytotalretail.com/article/beware-of-visual-bugs-compromising-user-experience/