unrecognized input file format

[getlose]

I just run Ionic build android --minify and got this error.

events.js:141
      throw er; // Unhandled 'error' event
      ^

Error: Command failed: Unrecognized input file format --- perhaps you need -targa

    at ChildProcess.onExit (D:\protomobileag18\mobileag18\node_modules\mozjpeg-stream\node_modules\duplex-child-process\index.js:116:12)
    at ChildProcess.g (events.js:260:16)
    at emitTwo (events.js:87:13)
    at ChildProcess.emit (events.js:172:7)
    at maybeClose (internal/child_process.js:818:16)
    at Process.ChildProcess._handle.onexit (internal/child_process.js:211:5)

Error: Hook failed with error code 1: D:\protomobileag18\mobileag18\hooks\after_prepare\ionic-minify.js

the most of the filename contain in the application image directory is xxxxxx.svg.png

are those files unrecognized by ionic-minify?
and what format types are supported by this ionic-minify?

Thanks