Understanding Images

Applies To: Windows 7, Windows Server 2008 R2

This topic defines the concept of imaging as it pertains to deploying the Windows® operating system.

What is an Image?

In the context of Windows deployment, an image refers to a copy of an installed operating system captured using an imaging solution. The imaging solution captures and compresses the content of a hard disk into a single file. The file is then deployed onto other computers, using the same imaging solution to unpack the files into its original format and layout. This method is known as image-based deployment. It is considered more efficient and reliable than manually installing the operating system on each computer one by one. Image-based deployments are common among computer-manufacturing environments and corporate deployments.

To learn more about other deployment methods, see Preinstallation Methods

ImageX and WIM Files

ImageX is a Microsoft imaging tool introduced during Windows Vista®, along with its new file format called Windows image. ImageX is a command-line tool that enables original equipment manufacturers (OEMs) and corporations to capture, modify, and apply file-based disk images for rapid deployment.

A .wim file is a file-based disk image format. Windows image (.wim) files are compressed packages that contain a number of related files. The format of a .wim file is optimized for maximum compression with an LZX algorithm, for fast compression with XPRESS, or uncompressed. In this documentation set, the term image commonly refers to a Windows image (.wim) file.

For more information, see ImageX Technical Reference and Windows Imaging File Format (WIM).

Image Design and Deployment

There are various image-design considerations when building your deployment environment. Since the release of Windows Vista, the Windows deployment architecture supports many different customization points during the deployment process. In the following deployment illustration, you can see the various points where you can customize your installation.

Defining your image early in the deployment process ensures a stable, consistent image. You can thoroughly build and test your installation in a lab environment prior to deployment. This design is the fastest method for deploying Windows, because there is minimal time spent on the factory floor. This is sometimes called build-to-plan (BTP).

If you use customizations during the deployment process, you have several options. For example, you can create an installation that will boot into audit mode, which enables you to include more customizations prior to delivery. This is sometimes called build-to-order (BTO).

When designing your images and deployment process, consider the following areas:

Maintenance

Image maintenance, or how long you plan to maintain your image, will influence the type of image you create. When software updates are released, your image becomes out-of-date. If you build an image for each model, and then multiply the number of images by the number of languages you support, the overhead required to update each image maybe too costly. You must decide whether to create a new image or incorporate the updates during the deployment process. Both options will introduce more time and, ultimately, delays in your deployment environment. To learn more about servicing an image, see Understanding Servicing Strategies.

Single Image Strategy

To reduce the number of images to maintain and service, you can implement a single image strategy. In Windows® 7, you can take advantage of the redesigned Windows imaging and Windows edition-servicing commands, which support changing one edition of Windows 7 to a higher edition within the same edition family.

However, this strategy requires additional processing during the deployment process. For example, to maintain edition-specific customizations, you must apply your customizations after the edition upgrade. If your business model does not support factory-floor customizations, this option will not work for you. For more information on this feature, see Windows Edition-Servicing Command-Line Options.

Multilingual Strategy

You can add multiple language packs in your image to reduce the number of language-specific images you support. During the deployment process, you can determine which language packs to preserve on the computer, as well as remove the unwanted language packs. This strategy will reduce the number of images you must maintain, but will add time to your deployment process and the end user's first boot experience. For more information on multilingual support, see Understanding Multilingual Deployments.

See Also

Concepts

Create a Windows Image for Multiple Architecture Types
Best Practices for Image Deployment