Now we have established that you have created a copyright work with your card, who owns the copyright in it?
The correct answer is that the author owns the copyright: s.9(1) of the Copyright Designs and Patents Act provides that an ‘author’ means a person who creates it. The person who created the card (fixed the work in a material form) would be the author. There are, however, three exceptional cases in which the author of a work is not the first owner of the copyright in it:
Where the work is a literary, dramatic, musical or artistic work or a film, and is made by an employee in the course of employment. Here the first owner of copyright is the employer.
Where the work attracts Crown or Parliamentary copyright.
Where the work attracts copyright by a designated international organisation, e.g. United Nations and its specialist agencies and the Organisation of American States.
If you want to know more about authorship, please read: Who owns copyright in a work?