To compress an animated GIF, shrink its width first, then lower the frame rate and the number of colors. Those three changes cut the most. If the file is still too big, turn it into an MP4. You can do all of this on your Mac without uploading anything.

A GIF is an old, clumsy format. It stores every frame almost whole, with a small color palette. That is why a short clip can weigh more than the video it came from.

The four things that make a GIF big

Every size problem comes from one of these. Fix them in this order.

  1. Width and height. Halve the width and each frame holds about a quarter of the pixels. This is the biggest win and the one most people skip.
  2. Frame rate. Fewer frames, smaller file. Most screen recordings look fine at 10 to 15 frames a second.
  3. Colors. Cutting the palette in half, and then in half again, costs little on a flat screen recording. It hurts photos and gradients more.
  4. Length. Trim the dead seconds at the start and end.

Change one thing, check the result, then change the next. Do not cut all four at once, or you will not know which cut hurt.

Option 1: gifsicle, free, in Terminal

Gifsicle is the free tool most other GIF optimizers are built on. Install it with Homebrew:

brew install gifsicle

Then run it on your file:

gifsicle -O3 --colors 128 --resize-width WIDTH input.gif -o output.gif

-O3 stores only the pixels that change between frames. --colors lowers the palette. --resize-width sets a new width (replace WIDTH with a number of pixels) and keeps the shape.

The drawback: it is Terminal only, and you guess the numbers until the file looks right.

Option 2: ImageOptim, free, drag and drop

ImageOptim is a free Mac app. Drop a GIF on it and it re-packs the file without changing how it looks. It does not resize the clip or cut colors for you.

The drawback: a GIF that was already tidy shrinks only a few percent. If you need a big drop, you still have to resize first.

Option 3: Picmal, local, with a compression level

I make Picmal, so weigh this one with that in mind. It is a Mac app that compresses and converts images, video, audio and PDFs on your Mac. Files never leave it.

For a GIF you drop the file in, pick a compression level, and save a smaller copy. A higher level gives a smaller file and a bit less detail. Try one level, look at the clip, then go up or down.

Picmal is worth it when you have many GIFs, or when you also compress other files. The batch guide shows how a whole folder works, and the Finder right-click menu lets you start from Finder.

The drawback: it is a paid app (one-time purchase, with a 7-day free trial and a 14-day refund). For one GIF, gifsicle costs nothing. The image compression page lists what it handles.

When to stop compressing and switch to MP4

Sometimes the GIF is the wrong format. A long clip with real motion will stay heavy however hard you squeeze it.

An MP4 or WebM video of the same clip is far smaller, and it often looks better. Many sites and chat apps play it on a loop, without sound, like a GIF. Some places still only accept a real .gif, so check before you switch.

With ffmpeg, from Terminal:

ffmpeg -i input.gif -movflags faststart -pix_fmt yuv420p -vf "scale=trunc(iw/2)*2:trunc(ih/2)*2" output.mp4

The scale part rounds the size to even numbers, which MP4 needs.

Why not an online compressor?

Online tools are quick for a throwaway clip, and some do the job well. But you upload the file, and many cap how big it can be. If the GIF shows a work screen or a client’s product, I would keep it on my own Mac.

What I would do

Resize it first, then lower the frame rate, then cut colors. If you still miss your size limit, use MP4. For a single file, gifsicle is enough. For a pile of them, try Picmal’s 7-day trial.

I send a short note when something new ships. The signup is in the footer below.