With the rapid spread of internet, it has been a social issue to preserve the use of the internet sanity. In general, average users cannot check the appropriate use of their network such as home network, because certain expert knowledge of network will be required. Therefore, we studied the method to allow general users to review outline of network use and implemented a prototype system Image Depot for checking inappropriate use of internet. It focuses on the images in the network communications. In recent years, a number of websites are made up of many graphics data as rich expression. Therefore, we can scan the contents of network communications quickly by extractiong images with our system.