local PlayerImage = game.ReplicatedStorage:FindFirstChild("PlayerImage")
local NPCImage = game.ReplicatedStorage:FindFirstChild("NPCImage") -- the RemoteEvent in ReplicatedStorage called "NPCImage"
local Players = game:GetService("Players")
local ThumbnailType = Enum.ThumbnailType.HeadShot
local ThumbnailSize = Enum.ThumbnailSize.Size150x150

PlayerImage.OnClientEvent:Connect(function(RandomPlayer)
    script.Parent.Image = Players:GetUserThumbnailAsync(RandomPlayer.userId, ThumbnailType, ThumbnailSize)
end)

NPCImage.OnClientEvent:Connect(function(NPCImage)
    script.Parent.Image = "http://www.roblox.com/asset/?id=0" -- Replace "0" with your Decal ID
end)