savePNG(file, [showOptions])
Exports the current document as PNG (or sequence of PNG files) to the documents folder. Please note, that export options default to the last used export settings.
Type: function
Parameter(s):
- file {String | File}:The file name or a File instance 
- showOptions {Boolean} Optional:Whether to show the export dialog 
Returns:
- 
    {File}:
 The exported PNG file.