***/Image/[email protected] pngcrush caught libpng error: Not a PNG file..
应用在在模拟器上调试一点问题没有，但一放到真机上调试就出现copypngfile 的错误，编译器报错信息如下：
While reading /Users/avepoint/Desktop/**/**/Image/[email protected] pngcrush caught libpng error:
Not a PNG file..
Command /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/copypng emitted errors but did not return a nonzero exit code to indicate failure
CopyPNGFile /Users/avepoint/Library/Developer/Xcode/DerivedData/**-eapmjmcpwpwpvcazuqcyashswpze/Build/Products/Debug-iphoneos/**.app/hsj.png **/Image/hsj.png
cd /Users/avepoint/Desktop/Melon/XMPPWorking_realPhone/**
export PATH="/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin:/Applications/Xcode.app/Contents/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/copypng -compress /Users/avepoint/Desktop/**/**/Image/hsj.png /Users/avepoint/Library/Developer/Xcode/DerivedData/**-eapmjmcpwpwpvcazuqcyashswpze/Build/Products/Debug-iphoneos/**.app/hsj.png
错误信息提示说读取图片的时候没有找到这张图片，检查了一下图片路径，没有问题。
解决方案：
1.在build settings里把工程里的Compress PNG files设置为NO，问题解决，但这样设置以后，弄出来的ipa会很大。
2.mac中用preview(预览)打开出问题的png文件，然后重新导出png文件或者用photoshop把png图片保存为NOT INTERLACED(不交错)的，覆盖源文件。这样真机调试时就没有错误了