OTClient OTClient - show image during 30 seconds

[roriscrave]

function Creature:onGiveIcon(Id)
    local imagePath = "/images/game/shield_icon"

    if imagePath then
        self:setGiveIcon(imagePath)
    end
end

I see this code in one server, when player use spell, it generete a img (shield icon), next to the character's head for 30 seconds and then disappears.
I don't know what the other part of the code is, how can I do that?
I need a code in OTC that will generate an image (shield icon) on the side of the player's head for 5 seconds, after carrying out the action (utana vid spell)