Yes, but you would need MCpatcher to do so.
It's a series of add-ons to minecraft that allow you to change how the game looks.
You just download a texture pack online, open you're texture pack folder through minecraft (or %appdata%), drag the texture pack into the folder, and select it though minecraft.
Get a texture pack
Download the texture pack and put it into the Minecraft Texture Pack folder.
To change the credits on a texture pack in Minecraft, locate the pack.mcmeta file within the texture pack's folder. Open this file with a text editor and find the "description" field, where you can modify the text to reflect your desired credits or information. Save the changes and ensure the texture pack is correctly loaded in Minecraft for the updates to take effect.
You can't unless you have a mod, hacking into Minecraft, or have a texture pack.
For Minecraft Oasis, the texture pack used by Cupcake is the FNI Realistic RPG texture pack. It can be found at Planet Minecraft.
Try Soartex HD pack ITS GREAT ...................... DIAMONDS! :P
As of the latest update, sadly, no.
Texture packs are downloadable files that change the appearance of the game. In minecraft it can change everything from the appearance of the blocks to the mobs and sometimes the default player skin.
you get a .zip of the texture pack, and copy it into the texture packs folder in the minecraft directory
You need to make sure that the texture pack is saved in the minecraft folder in the texture pack folder.