The craft stamp industry is very large indeed and most people are still buying stamps that are mass produced because they don't know how to get a 'custom made' stamp manufactured. So if you are into card making or scrapbooking and want to find that 'special stamp' you should find yourself a manufacturer, it doesn't matter where they are in the world as unmounted stamps are thin and lightweight and can be posted easily.
If the occasion is say the arrival of a girl, then the theme of the invitation card as well as that of the party will be for a girl. In these cases, baby clip art photos are to be used. You may opt to send either printed invitations or invitations via the Internet. The huge stocks of baby clipart pictures enable one to make a distinct choice. One can further give a personalized touch to the cards by innovative use of ideas and words.
Something to remember is to never use artwork unless you know it is in the public domain. Many popular images such as cartoon characters, logos, comic book characters, pictures of movie stars and signers are copyrighted. This means you could get into legal trouble by using such images without paying for them or getting permission.