Whereas STI only provided a low-level interface for doing basic transfers of data to and from the device (as well as the invocation of an image scan process on the Windows machine through the external device), WIA provides a framework through which a device can present its unique capabilities to the operating system, and applications can invoke those features.
[2][3] In 2002, Microsoft released the Windows Image Acquisition Automation Library Tool, which provides access to WIA functionality through programming languages and scripting environments that support OLE Automation.
Because of the security ramifications of running a service as LocalSystem whereby a buggy driver or malicious person would have unrestricted access to the system, the WIA service in Windows Server 2003 and Windows Vista operates in the LocalService context.
This can result in compatibility issues when using a driver designed for Windows XP.
However, video content support is removed from WIA for Windows Vista.