The line you are using is wrong, that's why it doesn't work.

There is an export example on this page: http://www.extrapixel.ch/processing/gifAnimation/

No, you didn't understand my question. Sorry if that wasn't clear. I'm not trying to export the gif, i'm trying to save it within the program. Is there a way to do this?

finish() is called within the program...
What you want isn't clear.

If you want to reuse the animation in the program itself, just keep the frames and show them successively.

Ah, I see what you mean. Looking at the instructions and source code, the answer is no. The classes for playing and exporting gif's are quite different. Each made for their specific purpose. I suppose you have a couple of different options.

1. Re-import the exported gif right after saving it.
2. Use an array of PImages instead (and an array of ints if you want custom delays).
3. Extend the Gif class to allow for adding images to a Gif or create a gifExport-to-Gif transition class/method.

Option 1 is the easiest.
Option 2 is doing manually what the Gif class does in the background.
Option 3 is taking the library as a starting point and extending it's features.

Are there any other gif libraries that might help? I think I might have to try option three..... How would I even start?

To answer your first question, there are currently no other gif libraries for Processing.

For future reference let me just add that if one was to choose option 2 these are useful:

• Processing > File > Examples > Topics > Animation
• Animation example by Shiffman: http://www.shiffman.net/tag/animation/
  

With regard to option 3. I don't know what kind of solution you want to implement exactly, but a starting point would be to look at the existing source code to understand how the library operates behind the scenes. Of course extending classes would require at least a basic knowledge of object-oriented programming and inheritance.

What's really frustrating is the guy that made it seems to have jumped ship off the internet. All of his social media websites haven't been visited in at least a year. I guess i'll try option three blindingly. Probably won't work. (That's the spirit)