**System Information**
Mac OSX Mavericks, MacBook Pro (external display) ... more details available if necessary.
**Blender Version**
Broken: 2.70 TEST BUILD for Mac OSX (Splash screen says Blender 2.69; Date: 2014-02-20 05:32; Hash 4789793)
**Short description of error**
UV Image Editor, create new image (Image->New Image) causes crash IF you unwrap mesh first.
**Exact steps for others to reproduce the error**
1. In default scene, select default cube, press TAB to Edit Mode, press "U" to Unwrap
2. Change view to UV/Image Editor, select Image->New Image from Menu
On my system, these steps cause a crash every time.
Feel free to contact me if you need more details.