What type of file (.JPG, .PNG, etc...) must I use to replace the default logo for a school or conference with one of my own? What size must the file be? Please help...having trouble.

The icons are 125x125 pixel .gif files.

Thank you! Any suggestions where I can find said logos to download or edit to size?

The "College Mod 21" has logos for every college and conference. You don't have to create anything...just load whatever version of that mod you want when you create your association and the correct logos will be automatically installed.