Looking to save some space with those high-res screenshots you took on your Retina machine? Skitch for Mac now allows users to chose between 144 DPI and the regular 72 DPI screenshots on those more pixel-dense displays. The new feature can be toggled via the file type menu at the bottom left of the app's window and doesn't affect the size of files sent to Evernote. Those larger screen captures are labeled "Hi-Res" the moment they're snapped and the software remembers your settings preferences as well. You can start slimming down your image library now, as the update is currently available via iTunes.