Webcamviewer_XH facilitates displaying an image, that will be refreshed after some customizable interval. Its intended use is to display the current snapshot of a webcam, which places the most recent image in the same place.
Changes are listed in the changelog. For further details you can read the manual online.
If you have already installed at least version 1rc1, you can download and install the patch. This won't overwrite any config, language or css files.