In an effort to have a feel of professionalism will use a image for their signature. While this may look better than just text, and have a more professional feel, this is literally only skin deep. A single image containing your logo, who you are and your contact information is fundametally flawed. First text in an image will never look right, nor as crisp as actual text. Second much of a signature should be interactive, such as the phone number or website, which can be when everthing is a flat image. This will completely annoy and off-put your customers reading your emails on their phones (which most are today).

As a business, you want to always project a sense of professionalism. Most people today interact with large Fortune 500 companies at some capacity regularly, and without realizing it expect the same level of professionalism everywhere. A professional email signature is a simple and econmic way to identify your team a professional and established organization.