etc1tool is a command line utility that lets you encode PNG
 images to the ETC1 compression standard and decode ETC1 compressed images back to PNG.
The usage for etc1tool is:
etc1tool infile [--help | --encode | --encodeNoHeader | --decode] [--showDifference diff-file] [-o outfile]
This table lists the command options:
| Option | Description | 
|---|---|
| infile | The input file to compress. | 
| --help | Print usage information. | 
| --encode | Create an ETC1 file from a PNG file. This is the default mode for the tool if nothing is specified. | 
| --encodeNoHeader | Create a raw ETC1 data file without a header from a PNG file. | 
| --decode | Create a PNG file from an ETC1 file. | 
| --showDifference diff-file | Write the difference between the original and encoded image to diff-file. This option is only valid when encoding. | 
| -o outfile | Specify the name of the output file.
      If outfileis not specified, the output file is constructed
      from the input filename with the appropriate suffix (.pkmor.png). | 
