In this study we evaluate visual quality of watermarked images, displayed on mobile devices. We consider a watermarking technique in spatial domain and embed a watermark into an image. We tested 3 different types of images and for each image 5 values for watermarking magnitude were tested. We tried to find out is there a difference in human evaluation of visual quality of watermarked image, depending on image properties and properties of a display. In visual assessment test we used a mobile phone, PDA, and CRT. The visual quality of watermarked image was evaluated by a set of human observers. The results were studied using statistical testing, which showed how does effect image type on perceptual quality of a watermark image.