With SCCM 2012 there are many components you can now add directly from the SCCM admin console that allow you to enhance your boot image with extended capabilities (Such as Powershell!) There are a variety of components to choose from, some easy to grasp what they add based on the name, others maybe not so easy.
Here’s a shot of the default x86 boot image (with default components).
Click the orange star to see the additional optional components you can add:
If you select new components to add you will be prompted to update your Distribution Points. This is the process that combines the new components into your PE WIM file and distributes the updated WIM out to your DP’s. You can always select no at this prompt and do it at a later time if you are super bandwidth conscious.
Here’s a TechNet article that describes each component in detail to help you determine if the added functionality is something you could utilize. As a best practice, you should only add components you plan on taking advantage of to keep the size of your boot image as small as possible. 😉