I use the amazing gifsicle on a nearly daily basis to resize, optimize, and modify animated GIFs for pull requests. I recently found myself growing tired of the command-line interface however, and decided to write a UI wrapper for it, which I've released as open source.

GIFPop is a simple & free animated GIF editor for the Mac, written in Swift. It is a minimal UI wrapper for gifsicle that exposes a few of the most commonly-used features, including: resizing, optimizing, trimming, and basic color table adjustments.

How To Use

Drag a .gif file onto the preview pane, or hit Cmd-O to select Adjust the size by entering a new width or height, or using the slider Choose any other trimming, optimization, or color table options Click Save GIF...

Optimization

GIFPop provides access to gifsicle's 3 primary optimization modes:
O1 - "Stores only the changed portion of each image."
O2 - "Also uses transparency to shrink the file further."
O3 - "Try several optimization methods (usually slower, sometimes better results)"

Download GIFPop

Source code: http://github.com/matthewreagan/GIFPop
Prebuilt binary: GIFPop.zip (Last update: 10/16/2016)

Work In Progress

As noted on the README, GIFPop is still a work-in-progress.
If you find any bugs (small or otherwise) please file an issue or reach out to me directly.

Happy GIF making!