Due to the COVID-19 epidemic, the use of web conferencing systems has become widespread but many people are not likely to send their own camera images. Muting the camera is usable to hide a participant but other participants can not aware the hided participant’s non-verbal information. The purpose of this study is to investigate how the ease of conversation is affected when the participants are displayed as avatars instead of actual images in a web conferencing system. For the purpose, we investigated whether the fidelity of participant’s image influence on the ease of conversation experimentally. We used four kinds of participant’s image, they were default still image, avatar image, point image, and real image. Experimental result showed the possibility that the avatar facial image reduced the participant’s embarrassment. Some participants felt that the system using avatar or point image improved the ease of conversation compared to the system using default non-moving image or real image.