IGNORE THE STRANGE GREY BACKGROUND! - it works the same as any other stamp: transparent and everything.
With all the excitement of Pottermore's pending public release approaching, I thought it was appropriate to make stamps of the official Pottermore Hogwarts House crests so deviants can (when they finally get the opportunity to be officially sorted) proudly show off which house they belong to. If you're one of the lucky people to already know your house, feel free to use whichever one you've been sorted into!
If this isn't the house you belong in, never fear! The other houses can be found here:
GRYFFINDOR HOUSE LETTER:
Congratulations! I’m Prefect Percy Weasley, and I’m delighted to welcome you to GRYFFINDOR HOUSE. Our emblem is the lion, the bravest of all creatures; our house colors are scarlet and gold, and our common room lies up in Gryffindor Tower.
This is, quite simply, the best house at Hogwarts. It’s where the bravest and boldest end up – for instance: Albus Dumbledore! Yes, Dumbledore himself, the greatest wizard of our time, was a Gryffindor! If that’s not enough for you, I don’t know what is.
I won’t keep you long, as all you need to do to find out more about your house is to follow Harry Potter and his friends as I lead them up to their dormitories. Enjoy your time at Hogwarts – but how could you fail to? You’ve become part of the best house in the school.
Gryffindor & Pottermore (c) J.K. Rowling