usage: addbevel inimage outimage [width][r g b][-sgi]
addbevel can read gif and rgb formats and output both as well. The correct file format of the input image file is determined by the file extension so this must be correct. For GIF-format, use either .gif or .GIF. For SGI's RGB-format, use .rgb or .RGB.
addbevel saves to GIF-format as a default but can save to RGB if the -sgi option is given at the end of the command line. (see usage) If no width is given, it defaults to a width of 5 pixels.
The color of the bevel defaults to gray if no rgb values are given for the bevel. Otherwise, it will take the rgb triplets which can be a range from 0..255.
no bevel
% addbevel eye.rgb eye1.gif
% addbevel eye.rgb eye2.gif 10
% addbevel eye.rgb eye3.gif 30
% addbevel eye.rgb eye4.gif 10 80 10 120