Allow me to introduce you to NSBitmapImageRep, which holds the dubious honor of being initialized by the longest public selector in all of Cocoa. Here's a contrived example:

  NSBitmapImageRep *rep = [[NSBitmapImageRep alloc] initWithBitmapDataPlanes:data
                                               pixelsWide:640     pixelsHigh:480
                                            bitsPerSample:8  samplesPerPixel:3
                                                 hasAlpha:NO        isPlanar:YES
                    colorSpaceName:@"NSCalibratedRGBColorSpace" bitmapFormat:NULL
                                              bytesPerRow:0     bitsPerPixel:0];