(from http://www.macgasm.net/2011/05/23/disable-dropshadow-mac-os-window-screenshots/)
defaults write com.apple.screencapture disable-shadow -bool true
killall SystemUIServer
(from http://www.macgasm.net/2011/05/23/disable-dropshadow-mac-os-window-screenshots/)
defaults write com.apple.screencapture disable-shadow -bool true
killall SystemUIServer