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I was interested to see how easy/difficult it is to edit the animated GIF "videos" pico8 produces. My goal was to trim some frames from the beginning and end to make a more succinct recording.

After much trial, error and experimentation here are my findings using Mac OS X.

Animated GIFs can be:

  • viewed frame-by-frame using macOS Preview.app
  • manipulated using "gifsicle" command line tool
  • converted using "ffmpeg" command line tool


  • useful tools need to be installed using "brew" command line tool http://brew.sh


Open the GIF in Preview.app and it will show you all frames.
Preview calls the first frame 1 (one), but other tools usually call it 0 (zero).

original/source animated GIF:


required: gifsicle

brew install gifsicle

then this is how you trim

gifsicle anim.gif "#212-238" > trimmed.gif

note: this makes a copy of the GIF and keep frames 213 to 239 (gifsicle uses zero based frame count)


if you want to double size of the image:

gifsicle --scale 2 trimmed.gif > resized.gif


if you want to add an overlay to caption the animation

required: imagemagick

brew install imagemagick

then use this bash script:

: ${1?"Usage: $0 anim.gif overlay.gif [output.gif]"}
: ${2?"Usage: $0 anim.gif overlay.gif [output.gif]"}

fnsource=$(basename "$source" .gif)
fncaption=$(basename "$caption" .gif)


gifsicle -E $source
for f in *.gif.*; do composite $caption $f $f; done
gifsicle --loopcount *.gif.* > $output
rm *.gif.*

how to run the command

./caption.sh anim.gif overlay.gif [output.gif]

note: if you do not specify an output name, it will be named using original filenames, eg. anim-overlay.gif



required: ffmpeg

brew install ffmpeg

to convert the GIF to MP4:

ffmpeg -i trimmed.gif video.mp4

video uploaded to YouTube:


If there is enough demand I will create a trimming tool that does not require you load terminal every time.

P#22961 2016-06-15 20:26 ( Edited 2020-07-04 12:03)

Resize command now done using gifsicle rather than ffmpeg for sharper results

P#22985 2016-06-16 09:11 ( Edited 2016-06-16 13:11)

Added example animations, images and video.

P#22994 2016-06-16 11:15 ( Edited 2016-06-16 15:16)

Hey there, thanks for writing this up. I just wanted to add to this that you can also tell gifsicle to super-optimise your GIFs by adding the option -O3 on the command line. This removes redundant frames, and also only leaves parts of frames where the image has changed. I also recommend using the --careful flag with this, to do it in a way that makes the GIFs more compatible across different viewers.

So you could do this using a command like:

gifsicle -O3 --careful input.gif > output.gif
P#24607 2016-07-05 04:28 ( Edited 2016-07-05 08:29)

Good point!

If you do use optimise, -O, and you want to edit the GIF further then be sure to use -U to unoptimise it otherwise the editing commands won't work as expected. This is the reason I left it out.

If in doubt, optimise a copy of your animation.

P#24651 2016-07-05 17:06 ( Edited 2016-07-05 21:06)

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