Custom Icon for commands

So I have been struggling with this for a bit. I am using a plugin called Heli Signal and want to give it the icon that is used in the skin.

I have tried the following:

  "commands": {
    "Heli Signal (Easy)": {
      "description": "Heli Signal (Easy)",
      "customIcon": "https://rustnation.us/imgs/SupplyEasy.png",
      "commands": [
        "hsgive easy $player.id 1"
      ],
      "displayName": null,
      "cost": 10,
      "cooldown": 0​
And 

  "commands": {
    "Heli Signal (Easy)": {
      "description": "Heli Signal (Easy)",
      "iconName": "https://rustnation.us/imgs/SupplyEasy.png",
      "commands": [
        "hsgive easy $player.id 1"
      ],
      "displayName": null,
      "cost": 10,
      "cooldown": 0​

And neither seem to work.
I also tried putting the png files in an Images folder inside ServerRewards "oxide/data/ServerRewards/Images/SupplyEasy.png" and that didn't work either.

Any ideas as to what I am doing wrong?

I am sure it is something simple.

You ever find the answer?