To set your server’s icon, follow these steps:

Login to Minecraft server’s panel
Click on Files
Click on FTP Access
Log in with your server’s panel credentials
Click on Upload
In the Files Section of the page, click on Choose File
Select your sever’s icon:

Image Requirements:

The icon needs to be in .png format,  if it’s not, convert it online, many websites offer this service for free.
The icon’s width and height needs to be 64x64, if it’s not, resize it with GIMP, MSPaint, or any other software that resizes images.
Your icon name must be server-icon.png

Click on Submit

Restart your server by clicking on Restart in the Servers tab

Published on: 06 / 06 / 2020