Any image can be used as a background template image. Try to format the image in a 5x3 ratio so it looks nice. If you want to be able to change the background card color then you will need to create a transparent image. If you don't then your background will still work but if you change card color you won't see the effect, since the card background is technically 'behind' the template image. We used PowerPoint to build the templates. We have many background templates in the app, but I would love to add more. If you have an idea for a new background template then please contact us and we'll help you build one and perhaps even add it to the app! I have created a new page on this site with 'User Provided' templates that you can download as images and use in the app as additional backgrounds.