Hi, this may occur on other versions of the game but it is not entirely clear yet.

If you have a Minecraft Singleplayer world and then create a minecraft server and import your singleplayer world from your private worlds folder to your server, the server will use the "icon.png" file in the worlds folder even though there is NO "server-icon.png" in the actual server folder itself. However I found that if you delete the "icon.png" in the world folder WHILE the server is running, and then run the reload command, the server will continue to use the same server icon even after refreshing the server list and running the command. If you shut the server down, then without changing anything; turn it back on, it will now have a completely blacked out icon. The server will show the icon as being completely black instead of the grayed out pack.png image which is typically used when a server has no icon. If the server is turned off, then turned back on AGAIN. It will display random minecraft textures. One time, I got the texture of the sun, another time I got a spider, a recent one (done maybe 5 minutes before making this post?) showed a cow (which i have provided pictures of)