This describes the operations in Image Manipulator.
Not a real operation, but fairly light load. The output is identical to the input.
Takes the top-left pixel as a mask. All pixels of the mask color are made transparent. Every other color is copied.
Performs a pixel transformation such that pixels that are similar to the selected input value will be transformed into being similar to the selected output value. All pixels will of course change, so the inverse will also happen. Not that in most cases switching the order of the inputs results in a perfect inverse.
There are seven colors on each side:
It's probably easier to say "Magic" than try to explain it, but I'll try: The process for converting images can be summarized as: if both colors are primary colors, the two corresponding channels are switched. Otherwise, a pixel's color is considered as a sum of two values, the primary value is the mean of the intensity values used in the channels of the specified color (the red channel for red, the red and green channels for yellow, all three channels for Black), and the secondary value the mean of the intensity values used in the other channels. The primary value is then inserted into the channels used by the output color and the secondary value is inserted into the remaining channels.
This behavior has a few useful effects: when Black is an input, the output image is a monochrome image in White and the output color. When Black is an output, the output is a monochrome image resembling the specified channel.
Strectches the contrast in an image. The dark parts will become darker, and the light parts will become lighter.
Turns an image into a black and white image. The grayscale value of a pixel is taken, and compared to a threshold value, determined by the slider. Any pixel with a greyscale value less than the threshold is made white, and any pixel with a grayscale value greater than the threshold is made black.
A bluring operation most commonly used for salt-and-pepper removal.
The parameter is the operation's window size: 3 up to 15.