PNG Options dialog box
[File > Export - Save As dialog box - Click Options], [File > Save As - Save As dialog box - Click Options]
- Range
Specifies what part of the document will be exported. If an export area has been defined, you can choose to export the export area only. If one or more objects have been selected on the Canvas, you can choose to export the selected object(s) only.
When you save a file, the whole document gets exported, irrespective of the export area.
- Interlaced
Select this option to export the current image as an interlaced PNG file. (When an interlaced image is loaded in a browser, it is initially displayed at a low resolution and then becomes sharper as the whole image file is loaded.) - Transparent
Select this option to export the current image with a transparent background. - File Size
Displays the file size to be exported. - Preview
Previews the image to be exported. You can zoom the image in or out with the Zoom In
and Zoom Out 
buttons.
