and what

In order to make a resource pack you need the base files which you can find in the minecraft.jar (the version your playing) and there is no longer a terrain.png the tile and item textures are broken up into separate images instead of a single group .png. To find these files you need to navigate to your roaming (search %appdata% in your start menu) then navigate to .minecraft then versions then select the version which you want to use. open the folder with it's name inside there should be a .json and .jar open the .jar with winrar or 7zip (archivers) inside of the .jar there are 3 folders 1 marked assets another marked META-INF and another marked net, there are also lots of classes, don't mess with those. Open the folder marked assets, copy the folder named minecraft to somewhere else, and thats your resource pack base rename the folder whatever you choose and edit with some image editor. I'm fairly sure that windows 7 comes with paint stock if not get gimp or another free editor, unless your like me and want to pay $800 for photoshop :P.