If the picture is colored black and white, that means that there is a file inside of the .zip that you just need to remove and put into the texture pack folder.
I feel like most world resets occur because of a spawn that is surrounded by griefed structures and things of that sort. I usually just move the spawn to another part of the world and unload all of the griefed chunks on my server. That way it's like nothing ever happened
Remember, as long as there isn't any new items or blocks added, old texture packs will work fine in new updates. The texture packs broke in once 1.5 arrived because the texture pack system was changed.
