Legal Question in Business Law in Alabama

You will actually have two concerns, but they are both manageable:

1) Trademark Infringement - A trademark is an indicator on a product that signifies who produced the goods. If the cards are attached to the good, e.g. a tag in a shirt's collar, then the trademark on the card stands for the company that made the shirt, not the company that printed the tag. You would not be the infringer. If you have knowledge that you are printing trademarks for infringers, however, you could be liable as a "contributory infringer." Many companies add a screen in their checkout procedure on the website where the customer must confirm that they own the trademark and will only use the cards for legal purposes. It is in your best interests to have an attorney review any such disclaimers to ensure maximum protection (the law surrounding electronic "contracts" is very active and there are several specific ways you need to implement that portion of your website to comply properly, i.e. a checkbox that must be checked in order to proceed, all capital and possibly red lettering for critical sections, etc).

2) Copyright infringement - If the cards stand on their own, then the images represent who manufactured the card itself. The consuming public generally understands that the manufacturer of a card places their mark on the back of the card or even as a watermark and not the imagery on the front or inside. The front and inside images may qualify as an artistic work covered under copyright protection. The customer must own the copyright in order to grant you the license to make copies. To own a copyright, your customers must have created the work or purchased the rights from the creator (or fall into an exception that you would need to consult with an attorney to discover). In general, a "click" contract could require customers to state that they are the copyright owner.

For especially large orders, you may want to require proof of trademark and copyright ownership. And, in the event you ever receive a complaint from someone claiming you are violating their copyrights/trademark you should immediately stop production until you verify that your customer does indeed own the rights.