I made a resource pack and I tried to change the panoramic background of the title screen of minecraft, but it didn't work.

What I expected to happen was...:
Minecraft title screen background to change into the one I made in a resource pack

What actually happened was...:
The minecraft title screen didn't change but other textures did

Steps to Reproduce:
1. Make a resource pack with 13w25c
2. Take photos of each 6 directions to use
3. Place photos in assets/minecraft/textures/gui/title/background/
4. Zip the assets folder and the pack.mcmeta
5. Place the zipped file in MinecraftDev
6. Run MinecraftDev

I am attaching what I have of my resource pack (only a few items and the panorama) and photos of the issue