Unlike CoreGraphics images (MonoMac.CoreGraphics.CGImage) that are objects that hold the actual image data to be processed, CIImages represents a set of instructions to obtain an image. These recipes are used during the CoreImage filtering, analysis or rendering pipeline to actually create the bitmap representation.

CIImages are either the result of loading an image from disk, an NSData array, a CoreVideo buffer a CoreGraphics image, or the result of processing an image pipeline by CoreImage.

CIImages for example are used when chaining various filters (MonoMac.CoreImage.CIFilter) together and only their abstract representation is passed between the output of one filter and the input to another one. The image might not even reside in the main memory, it could reside entirely on the GPU space as an intermediate step between two filters.