How to add a server icon to your server: (Pterodactyl Panel)
1) Login to your control panel and locate your server.
2) Stop the server.
3) On the left hand side of the panel, locate and click File Management.
4) On the top right of your screen you will see a button called upload.
5) Press "Upload" and select your server-icon file. Ensure that the file is named server-icon and is 64x64 pixels and is in .PNG format.
5) After uploading, reload the page and start your server. Your server-icon should appear.
How to add a server icon to your server: (Multicraft Panel)
1) Login to FileZilla
2) Upload your file named server-icon.Ensure that is it 64 x64 pixels and is in .PNG format.
3) Restart your server.