As an essential step towards the Minecraft modding API, and also for sanity's sake in our own code, we're removing Texture Packs and replacing them with a new Resource Pack system. Ultimately, every mod/plugin will be its own resource pack, vanilla will be a resource pack by itself, and users will be able to apply multiple resource packs at once…

gistfile1.json

{
    "//comment": "All metainfo files will be ORIGINAL_FILE.mcmeta. For example, textures/blocks/portal.png.mcmeta. The format is, of course, JSON.",
    "animation": {
        "//comment": "This block will be required for animated textures. It can be an empty block, but it will be needed to detect an animation.",
        "frames": [
            1,
            {"index": 2, "time": 4},
            3,
            4
        ],
        "frametime": 2,
        "width": 2,
        "height": 5
    },
    "texture": {
        "//comment": "This block can go on any texture and it'll control how that is rendered out. Not yet implemented as of time of writing.",
        "blur": true,
        "clamp": false
    },
    "font": {
        "//comment": "Font files will have all their data serialized out so that we don't break the font trying to figure everything out ourselves. Not yet implemented as of time of writing.",
        "characters": {
            "default": {
                "spacing": 0.1,
                "left": 0.2,
                "width": 0.3
            },
            "0": {
                "spacing": 0.2,
                "left": 0.3
            },
            "1": {
                "spacing": 0.3,
                "width": 0.3
            },
            "2": {
                "spacing": 0.5,
                "left": 0.1,
                "width": 0.2
            }
        }
    },
    "pack": {
        "//comment": "This will be in your pack.png.mcmeta. It replaces pack.txt, and will contain more info in the future. Not yet implemented as of time of writing.",
        "description": "hello world!",
        "pack_format": 1
    },
    "//short_term_todo": "Sound registration, language registration"
}

I am having trouble animating the title image for the main menu (minecraft.png). I have successfully made a resource pack and have resized the original "textures/gui/minecraft.png" from 256x256 to 256x1536 (1536 / 256 = 6 frames). I have made a "textures/gui/minecraft.png.mcmeta" in the same directory as the .png and wrote in the "animation"{..} block. I have checked for syntax errors everywhere. The "width", "height" and "frametime" fields have also been specified. The frame array is specified like so:

"frames": [
0,
1,
2,
3,
4,
5,
4,
3,
2,
1
]

Where have I gone wrong? I used Notepad++ to edit the JSON. The result is the image showing up stuck between two of the frames. No change is observed as the frames are supposed to change.

--Bottom line--
1.6.1 pre: Unable to animate GUI image "minecraft.png" using new JSON format through "minecraft.png.mcmeta".

@Dinnerbone @grum I have to do to change my texture pack to a resource bundle?
my twitter is @dubstepgamer77

I can't begin to explain how pumped I am for the mod api and being able to have simple methods for players to connect to things like a tekkit server without conplicating the lives of average players.

WHOOOOOOOO!