In addition to the asthetics, you'll want to consider the format the art is provided in. Raster, or pixelized images do not give as good of quality in print projects as vector, or eps images. If you want to change the colors to match your school colors, and if the images are going to appear large (on a banner or sign), be sure to look for vector eps images. You will need some type of vector based illustration program to change the colors. Coreldraw and Illustrator are the two most commonly used programs. If you don't have one of these programs, check with the Web site provider of the clipart. In many cases, they are glad to make color modifications on your behalf for a modest fee.
Like any marketing tactic though, poor execution can have detrimental affects. A poorly executed cartoon brand mascot can undermine quality and value and tarnish your brand. Here are some do's and don't if you are considering using a cartoon brand mascot to promote your company, product or service:
A school mascot is much more than just a funny character running around the football field at halftime. A school mascot is one of the most critical elements of a school's brand.