1. Open a new, transparent image.
2. Add your images, text, patterns, whatever to the new image you just opened (they need to have transparent backgrounds). Now press the Print Screen button (usually next to F12), making sure you can see your whole layout.
3. Press Ctrl and V to paste your screenshot and then click and use it to go around the outside of your layout. Once you’ve cropped it to the right size, save! Here’s mine (I’m sure you’ll have a lot more time to spend on yours :P):