iOS 5.1 with Xcode 4.2 and retina in iPad 3

Question

i have a Mac with Mac OS X Snow Leopard, can i add iOS 5.1 to it?

With the new resolution for iPad 3, how we will do with images, because if the app will run in iPho

Answer 1

@WrightCS's answer handles the part about the images perfectly well.

However, you can get the simulator and SDK to run on Snow Leopard.

1. Download Xcode version 4.3.1 bypassing the AppStore from here http://developer.apple.com/downloads

2. Open up the package and copy

   /Volumes/Xcode/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Develop‌​er/SDKs/iPhoneOS5.1.sdk
   to 
   /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.1.sdk
   

3. Copy

   /Volumes/Xcode/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceS‌​upport/5.1
   to
   /Developer/Platforms/iPhoneOS.platform/DeviceSupport/5.1 (9B176
   

4. Copy

   /Volumes/Xcode/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/‌​Developer/SDKs/iPhoneSimulator5.1.sdk
   to 
   /Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator5.1‌​.sdk
   

Adapted from here.

Edit: Get your iPad Retina on by copying

/Volumes/Xcode/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/Applications/iPhone Simulator.app
to
/Developer/Platforms/iPhoneSimulator.platform/Developer/Applications/iPhone Simulator.app`