Things You'll Need
Instructions
Click the "Start" button and do a search for a file named "%appdata%" without the quotations. A folder named "Roaming" should pop up, open it and find the "Minecraft.jar" file inside.
Right-click "minecraft.jar" and select "7zip," or another extracting program you have installed, and choose "open archive." This will allow you to view all the "Minecraft" texture folders.
Find the folder named "art" open it. Select the file named "Kz.png" and right-click it, select "extract" to take it out of the archive.
Open the "Kz.png" file with an image editing program. You will now see all the default "Minecraft" paintings placed on a grid.
Edit the paintings or insert new image files to override the already existing images, by clicking "File" and select "Import." You must make sure that the new images completely overlap the already existing image, so resize any new images if necessary.
Once complete, save and close "Kz.png." Replace the old "art" folder in the "minecraft.jar" archive with a new "art" folder that has your edited "Kz.png" image file inside. This will replace the old paintings with the new ones.
Load "Minecraft" to test out the inserted paintings.