PNG Export of sheets is enabled by entering a valid directory path for Bitmap Output Directory when running the extension. The Export Complete Sheets Bitmaps DPI setting must be set as well.

One large PNG is generated in that directory for each sheet (front or back) generated by the extension.

A DPI of 90 or 100 is probably good enough to export sheets to display on a screen (maybe post on a web site as previews of a game). Higher values can be used for sheets to print, but for that it is probably better to use PDF Export instead.

To generate PNGs from each individual counters a column with header ID is required. Only counters that have an ID given in that column will be exported and the ID will be used as their filename. Do not use spaces of funny characters for counter IDs that will not work well as filenames or as id attributes for the generated counters (something that the ID column is also used for).

Set ID Bitmap Width and Height when running the extension to something larger than 0 to enable generation of the counter bitmaps. The Bitmap Output Directory must also be set (and the same directory will be used if generating both sheets and individual counters).

Individual counters as PNG can be used for previews to post online or to import them into a virtual game table application like VASSAL (although recent versions of VASSAL supports importing counters from larger sheets, to it is probably easier for that use-case to use exported countersheet bitmaps instead).