Doesn't work with CLI when quality option is set

[WangHansen]

Run the following command:
$ imagemin p12.png --plugin.pngquant.quality={0.1,0.2} > ./images/p12.png

I got:

ArgumentError: (array `options.quality`) Expected `t` to be of type `number` but received type `string`

[Allain55]

Any update on this? I get this error only if quality is set:

{
  shortMessage: 'Command failed with exit code 99: /%PROJECT_PATH%/node_modules/pngquant-bin/vendor/pngquant - --speed 1 --strip --quality 85-95',
  command: '/%PROJECT_PATH%/node_modules/pngquant-bin/vendor/pngquant - --speed 1 --strip --quality 85-95',
  exitCode: 99,
  signal: undefined,
  signalDescription: undefined,
  stdout: <Buffer 89 50 4e 47 0d 0a 1a 0a 00 00 00 0d 49 48 44 52 00 00 07 80 00 00 04 38 08 06 00 00 00 e8 d3 c1 43 00 00 20 00 49 44 41 54 78 da ec 9a cd 72 db c8 11 ... 5192639 more bytes>,
  stderr: <Buffer >,
  failed: true,
  timedOut: false,
  isCanceled: false,
  killed: false
}

Bug introduced in v9.
It doesn't affect every image, don't know what's the difference

[gwicksted]

Error code 99 from pngquant means:

If conversion results in quality below the min quality the image won't be saved (if outputting to stdout, 24-bit original will be output) and pngquant will exit with status code 99.

It causes gulp-imagemin to fail too rather than copying the original file.