how to change image ?

look at the image.Image ! how to change the image ?

local frame = Instance.new("Frame")
frame.Parent = screen

local image =Instance.new("ImageLabel")
image.Parent = frame
image.Image = rbxassetid://999999999        -- This please help
image.Position = UDim2.new(0.45,0,0.4,0)
image.Size = UDim2.new(0.25,0,0.5,0)