I started to use GifAnimation because i needed to load .gif and display them in my games. Then i wanted to zip all sprites files to make them faster to load. However GifAnimation request a filename to load .gif with InputStream and this is the only constructor. So I think, if you put a .gif file in a zip you can't load it with GifAnimation, and if you open this zip archive with UnzipIt, you can't load the gif after. So I added it to these libraries:

1. public Gif(PApplet parent, InputStream stream)  {
2.         super(1, 1, ARGB);
3.         this.parent = parent;
4.         GifDecoder gifDecoder = createDecoder(parent, stream);
5.         frames = extractFrames(gifDecoder);
6.         delays = extractDelays(gifDecoder);
7.         repeatSetting = gifDecoder.getLoopCount();
8.         super.init(frames[0].width, frames[0].height, ARGB);
9.         jump(0);
10.         parent.registerDispose(this);
11.         runner = new Thread(this);
12.         runner.start();
13. }

1. private static GifDecoder createDecoder(PApplet parent, InputStream stream)  {
2.       GifDecoder gifDecoder = new GifDecoder();
3.       gifDecoder.read(stream);
4.       return gifDecoder;
5. }

And in UnzipIt:

1. public InputStream getInputStream(PApplet p, String fname) {
2.       try {
               ZipInputStream in = new ZipInputStream(new FileInputStream(zip.getAbsolutePath()));
               ZipEntry entry = in.getNextEntry();
               while(entry != null && !entry.getName().toLowerCase().equals(fname.toLowerCase())){
                     in.closeEntry();
                     entry = in.getNextEntry();
               }
               return in;
         } catch(Exception e) {}
         return null;
3. }

So you can get an InputStream from a file in zip archive and you can make a gif from it. I don't know if someone already made it but it was useful for me.