Fixed an issue with OptiPNG 0.7 or higher
Fixed an issue with OptiPNG 0.7 or higher

Check the return code from OptiPNG instead of STDERR since OptiPNG outputs all activity logs into STDERR by default.

appcelerator/express-cdn,philipheinser/express-cdn,niftylettuce/express-cdn,sincraianul/express-cdn-wip,noikiy/express-cdn,aaronroberson/express-cdn,appcelerator/express-cdn,philipheinser/express-cdn,aaronroberson/express-cdn,niftylettuce/express-cdn,noikiy/express-cdn,Creative-Licence-Digital/express-cdn,sincraianul/express-cdn-wip