ARM template for deploying multiple VMs from a custom image

multipleVMs.json

{
  "$schema": "https://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "VnetResourceGroup": {
      "type": "string"
    },
    "VnetName": {
      "type": "string"
    },
    "SubnetName": {
      "type": "string"
    },
    "VMImageName": {
      "type": "string"
    },
    "AdminUsername": {
      "type": "string",
      "metadata": {
        "description": "Admin username for VM"
      }
    },
    "AdminPassword": {
      "type": "securestring",
      "metadata": {
        "description": "Admin password for VM"
      }
    },
    "VMNames": {
      "type": "array",
      "metadata": {
        "description": "Number of VMs to deploy, limit 5 since this sample is using a single storage account"
      }
    }
  },
  "resources": [
    {
      "type": "Microsoft.Network/networkInterfaces",
      "name": "[concat(parameters('VMNames')[copyIndex()], '-nic')]",
      "apiVersion": "2016-03-30",
      "location": "[resourceGroup().location]",
      "copy": {
        "name": "nicLoop",
        "count": "[length(parameters('VMNames'))]"
      },
      "properties": {
        "ipConfigurations": [
          {
            "name": "ipconfig1",
            "properties": {
              "privateIPAllocationMethod": "Dynamic",
              "subnet": {
                "id": "[concat(resourceId(parameters('VnetResourceGroup'),'Microsoft.Network/virtualNetworks/subnets',parameters('VnetName')),'/subnets/',parameters('subnetName'))]"
              }
            }
          }
        ]
      }
    },
    {
      "type": "Microsoft.Compute/virtualMachines",
      "name": "[parameters('VMNames')[copyIndex()]]",
      "apiVersion": "2016-04-30-preview",
      "location": "[resourceGroup().location]",
      "copy": {
        "name": "virtualMachineLoop",
        "count": "[length(parameters('VMNames'))]"
      },
      "dependsOn": [
        "nicLoop"
      ],
      "properties": {
        "hardwareProfile": {
          "vmSize": "Standard_D1_v2"
        },
        "osProfile": {
          "computerName": "[parameters('VMNames')[copyIndex()]]",
          "adminUsername": "[parameters('AdminUsername')]",
          "adminPassword": "[parameters('AdminPassword')]"
        },
        "storageProfile": {
          "imageReference": {
			"id": "[resourceId(parameters('VnetResourceGroup'), 'Microsoft.Compute/images', parameters('VMImageName'))]"
		  },
          "osDisk": {
            "createOption": "FromImage",
			"managedDisk": {
				"storageAccountType": "Standard_LRS"
			}
          }
        },
        "networkProfile": {
          "networkInterfaces": [
            {
              "id": "[resourceId('Microsoft.Network/networkInterfaces',concat(parameters('VMNames')[copyIndex()], '-nic'))]"
            }
          ]
        }
      }
    }
  ]
}