Pngcrush error after CLI 3.7.2 update

All my resources files for icons have become invalid during a build in IOS DEVICE not virtual instrument. The error or bug states. I then proceeded to update build for ionic CLI to 3.7.2 and still the same result.

 `pngcrush caught libpng error: Not a PNG file..`

All my files have the png extension. Any thoughts on this? Should I be creating my resource files in a specific workflow or is there CLI tools i need installed through Xcode or Eclipse? Thank you in advance.

Did you have any luck with this issue? Seeing the same error here.