In comparison to conventional displays, 3D stereoscopic displays convey additional information about the 3D structure of a scene by providing information that can be used to extract depth. In the present study we evaluated the psychovisual impact of stereoscopic images on viewers. Thirty-three non-expert viewers rated sensation of depth, perceived sharpness, subjective image quality, and relative preference for stereoscopic over non-stereoscopic images. Rating methods were based on procedures described in ITU- Rec. 500. Viewers also rated sequences in which the left- and right-eye images were processed independently, using a generic MPEG-2 codec, at bit-rates of 6, 3, and 1 Mbits/s. The main finding was that viewers preferred the stereoscopic version over the non-stereoscopic version of the sequences, provided that the sequence did not contain noticeable stereo artifacts, such as exaggerated disparity. Perceived depth was rated greater for stereoscopic than for non-stereoscopic sequences, and perceived sharpness of stereoscopic sequences was rated the same or lower compared to non-stereoscopic sequences. Subjective image quality was influenced primarily by apparent sharpness of the video sequences, and less so by perceived depth.