This is an elegant way to provide your contact information and picture at the end of a presentation. You've already spent a lot of money on your business card design, so why not use as a presentation element. You can either create/obtain a high-quality scan of your business card or have your graphic artist generate a jpg/png image from the production file (Adobe Illustrator or Photoshop) for you to use.
If you choose to use a photograph of yourself and/or your team members, make sure it is high quality. Consider having a photographer come in to take pictures of your team so that you have great pictures on hand for your website, presentations, brochures, etc. Also, remember that pictures of the team members should be consistent: instruct the photographer to keep the head size of each team member the same size and to photograph the same amount of body and background for each. This attention to detail will make sure that you and your team appear professional and capable.