Storing and Transferring Thumbnail Data

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WIA thumbnail information is controlled by three WIA properties: WIA_IPC_THUMBNAIL, WIA_IPC_THUMBNAIL_WIDTH, and WIA_IPC_THUMBNAIL_HEIGHT. In Windows Me, and in Windows XP and later, the thumbnail data is 24-bits per pixel only.

WIA_IPC_THUMBNAIL
The property contains the thumbnail data in RGB format, with 24 bits per pixel, and aligned on 32-bit boundaries.

WIA_IPC_THUMB_WIDTH
The property contains the thumbnail image width, in pixels.

WIA_IPC_THUMBNAIL_HEIGHT
The property contains the thumbnail image height, in pixels.

An application reads the WIA_IPC_THUMB_WIDTH and WIA_IPC_THUMB_HEIGHT properties to create the property BITMAPINFOHEADER structure (described in the Microsoft Windows SDK documentation). The application then reads the WIA_IPC_THUMBNAIL property for the actual thumbnail data. The thumbnail data should be uncompressed, 24-bits per pixel data aligned on 32-bit boundaries.