f == STRING filter name e.g. "invert" Default: null (required) "anaglyph"1.7 Creates a 3D anaglyph from a single image [no args] "invert"1.0 Reverses all colors of the image [no args] "invertalpha"1.0 Reverses the transparency of the image [no args] "grayscale"1.0 Converts the image into grayscale [no args] "solarize"1.0 Solarizes the image by negating the colors [no args] "sepia"1.0 Applies the well-known sepia coloring to the image [no args] "threshold"1.0 Converts the image to black&white...