When I build my app with Xcode 4 it always show this error message:
CopyPNGFile /Users/michaelchen/Library/Developer/Xcode/DerivedData/iMusicBox-boeawugacmhacbdtyymnprzfobyq/ArchiveIntermediates/iMusicBox/InstallationBuildProductsLocation/Applications/iMusicBox.app/list_cell.png Images/list_cell.png
cd /Volumes/WORK/Works/iMusicBox
setenv PATH "/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin:/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
"/Developer/Platforms/iPhoneOS.platform/Developer/Library/Xcode/PrivatePlugIns/iPhoneOS Build System Support.xcplugin/Contents/Resources/copypng" -compress "" /Volumes/WORK/Works/iMusicBox/Images/list_cell.png /Users/michaelchen/Library/Developer/Xcode/DerivedData/iMusicBox-boeawugacmhacbdtyymnprzfobyq/ArchiveIntermediates/iMusicBox/InstallationBuildProductsLocation/Applications/iMusicBox.app/list_cell.png
While checking alphas in /Volumes/WORK/Works/iMusicBox/Images/list_cell.png pngcrush caught libpng error: Not enough image data
but It's OK with Xcode 3.2 - why?
Found it!!
You have to save your PNG files as NOT INTERLACED. Try to open the file in photoshop (or similar), save as, and select "Not interlaced".
It is working in my case
hope this helps