Script takes two required arguments: input_filename.jpg output_filename.jpg and
next one of filters or modifiers argument with optionally addition parameters.

List of filters:
-h : shades of gray (8-bit).
-bw : black & white (1-bit monochrome).
-s : sepia.
-n : negative.
-f C: custom filter with C color argument: red, green, yellow and other rainbow,
or hex code (#AABBCC) of color or random.

List of modifiers:
-br N: multiple brightness on N.
-m N: scale image on N.
-bl k: blur image with k * k tile.