This is the classic war poster "Keep Calm and Carry On" reworded to "Keep Calm and Zombie On". I've kept the traditional crown at the top, and added zombies standing on the letters. It's a funny cool design, a bit different to other 'keep calms'. (See my store for more zombie designs too.)
I've put this on a red background, but you can change that really easily. Hit 'Customize it' and then 'edit', and you'll be able to change to absolutely ANY color you prefer.