We have since added this (Daily build 1214 or later)
Add the following line to your build.settings file
skipPNGCrush = true, -- true/false
Example:
settings = { iphone = { skipPNGCrush = true, } }
Please see this for more info: http://www.coronalabs.com/blog/2013/09/26/daily-build-roundup-win-simulator-android-transition-2-0-ios/
Thank you Danny, I have tried and it works! 
Hello guys,
Is this issue solved? It is very disappointing, PNGs gaining ~40% in size after pngcrush “optimization”
Please, please provide at least a hack to disable this!
We have since added this (Daily build 1214 or later)
Add the following line to your build.settings file
skipPNGCrush = true, -- true/false
Example:
settings = { iphone = { skipPNGCrush = true, } }
Please see this for more info: http://www.coronalabs.com/blog/2013/09/26/daily-build-roundup-win-simulator-android-transition-2-0-ios/
Thank you Danny, I have tried and it works!