Barrier coverage of sensor networks is to provide sensor barriers guarding boundaries of critical infrastructures. In order to increase the Quality of Monitor (QoM) of Wireless Visual Sensor Networks (WVSNs), we revisit the barrier coverage problem with the consideration of Importance of Image (IoI). With the consideration of IoI, we can ensure that if any intruder crosses the barrier, important portions of the intruder can be clearly captured. Moreover, we use two different deployment methods to observe the successful rate of the proposed barrier construction algorithm. The two deployment methods are Uniform distribution and Gaussian distribution.