I’ve enjoyed the ease of switching themes to one I’ve used before and having my header images fetched from the Media Library for me. I’ve also wished same was the case with background images and I’m going to my wish, along with legions of other WordPress users.
Here’s some of what’s new:
- Theme Customizer with Previewer
- Flexible Custom Header Sizes
- Selecting Custom Header and Background Images from Media Library
- Better experience searching for and choosing a theme
If you want to be a beta tester then you have to set up a local install of WordPress or have a WordPress.org site that you can install it on.
Download WordPress 3.4 Beta 1
how to report bugs
WordPress Core Trac
More reading > And what WordPress actually needs?