Aviz enables saving a rendering as a png file. Once there's a desired rendering one should press the Snap button, and immediately a png file under the name of the xyz file plus a numerical extension will be saved (in the same directory of the xyz file). For example if the xyz file used for the rendering is SPINOUT015.xyz the saved png file will be SPINOUT015.0001.png.
If Snap is pressed again (even if some change was made to the rendering e.g view point,color), another png file will be saved in the same directory with the same name and a consecutive numerical extension. In this example : SPINOUT015.0002.png etc.
The consecutive numerical extension way of saving will be in one's benefit when creating an animation of changing view point.
Also, one can click on File --> Snap PNG File to save a rendering under some other desired name and in some other directory.
Note that the shape and size of the display window are adjustable. Aviz saves the a png file in the same size and shape (rectangular shapes) of the display window.