When you create a new world the default Texture Pack screenshot is too compressed (compared to the other Texture Packs) to be useful. It's hard to imagine this being done on purpose. (Verified on multiple machines with different accounts)
What I expect to happen:
I expect to be able to identify something in the screenshot that illustrates the textures in the texture pack.
What actually happened:
It's a huge pixelated mess. I can only guess what blocks are represented by their color.
Steps to reproduce:
1. Open the Minecraft bubble. Click start at livearea screen
2. At Main Menu. Select "Play Game"
3. At Load/Create/Join tab menu. Select "Create" tab
4. Select "Create New World". (look at screenshot in bottom right corner)