Optimize animated GIF size in command-line

Use gifsicle (available for Mac OS X and Windows).

gifsicle -i anim.gif -O3 --colors 256 -o anim-opt.gif

This will optimize and reduce to 256 colors, if the animation uses more colors (the example image does).

You can reduce the size by reducing the number of colors:

512KB, 256 colors

412KB, 128 colors

340KB, 64 colors

240KB, 32 colors

140KB, 16 colors

Based on another Q&A.