ImageLabel not displaying on the screen?

I am working on a game and i want to make it where when a player joins the game, An image pops up. But when i tried this, the image didn't show up and the output isn't helping me. Help?

game.Players.PlayerAdded:connect(function(player)
    local gui = player:WaitForChild("PlayerGui")
    local screen = Instance.new("ScreenGui", gui)
    local frame = Instance.new("Frame", screen)
    frame.Size = UDim2.new(1,0,1,0)
    frame.BackgroundColor3 = Color3.new(0,0,0)
    local textlabel = Instance.new("ImageLabel", screen)
    textlabel.Size = UDim2.new(1,0,.8,0)
    textlabel.Position = UDim2.new(0,0,.1,0)
    textlabel.Image = "rbxgameasset://Images/Cool Text - Pokemon Adventures 213153883449122"

end)