Whether a thumbnail should be automatically created for an image if a thumbnail isn't present in the image source file. The thumbnail is created from the full image, subject to the limit specified by kCGImageSourceThumbnailMaxPixelSize. If a maximum pixel size isn't specified, then the thumbnail is the size of the full image, which in most cases is not desirable. This key must be a CFBoolean value. The default value is kCFBooleanFalse. This key can be provided in the options dictionary that you pass to the function CGImageSourceCreateThumbnailAtIndex.
Available in Mac OS X v10.4 and later.
Declaration Syntax Version Information- Available in Monobjc Bridge: 10.6 (For Mac OS X 10.6 and later), 10.5 (For Mac OS X 10.5 and later)