If you wish to upload an image to act as your server icon, you can by following this guide!
First off, make sure your icon has the following specifications:
Icon size: 64x64 pixels
Format: .PNG (Any other format, such as .jpg or .jpeg will not work)
When you have your icon ready, rename it to "server-icon.png" and log in to your control-panel. Once there, open up your file-manager. Check if there's an existing server-icon.png first, if there is, delete it.
When you've made sure there's no server-icon.png file in your directory, simply click "Upload". Select your icon from the browse-window that appears and click OK.
Restart your server and your icon will show up.