Optimizing (Compressing) GIF images in Photoshop


I am trying to optimize an animated GIF image in Photoshop. The current size is 2.2 MB. Following the guides I found online, they told me to "Save as Web" and then decrease the colors from 256 down to 128 or 64.

I tried that — however, when I try to decrease it, the size actually increased.

  • 128 colors = 4.4 MB
  • 64 colors = 5 MB

Does anyone know why this is happening?

Original (256 colors):


After (128 colors):

enter image description here

8/9/2013 4:50:00 AM

Fewer colors + 100% dither + no Transparency Dither = greater size.

Adding a transparency dither or reducing the color dithering to less than 100% will most likely reduce the file size.

When you reduce the color table and have a high dither setting, you ask Photoshop to dither with fewer colors. This actually creates more color data to maintain from frame to frame, thus increasing the file size. The fact that your animation has 157 frames with 100% dithering it wouldn't surprise me if the file size quadrupled due to the dithering setting.

If you are truly interested in reducing the file size, you need to prune at least half those frames. This is especially true if image changes between the frames are present for all 157 frames. You simply can't squeeze a blue whale into a tuna can.

8/9/2013 7:32:00 AM