Imagecolor3 not changing colors?

I am trying to make a script to make a script where it changes color of a imagebutton, but it does not work. Here is my script:

function onClicked()
script.Parent.Parent.Parent.Parent.Start.Roundify_12px.ImageColor3 = Color3.fromRGB(59, 118, 0)
    end
script.Parent.MouseButton1Click:Connect(onClicked)

The line "color3.fromRGB(59, 118, 0) doesn't seem to be working. Am i suppose to put the rgb value after it or something else?