OS X icons size

Question

What size should an application icon and menu bar icon for OS X be?

I can deal with small resolution displays but what about Retina - does an icon displayed on the men

Answer 1

Follow these steps and you will get a perfectly sharp status bar Icon for retina

1. Open a png file of your Icon in photoshop it should be larger than 88px x 88px
2. go to menu, Image, Image size
3. set resolution to 350
4. set size to 88px x 88px (pixels)
5. save image as png add it xcode