How do I make my image gradually get smaller on the screen when it covers it?

I'm trying to do a little animation to an image label that covers the screen and then gradually gets smaller until a certain size. The error is: X cannot be assigned to

local i = script.Parent.ImageLabel
function sizeX(a, b, c)
    for x = a, b, c do
        i.Size.X = Vector2.new({a, b, c}, 0)
    end
end

function sizeY(a, b, c)
    for y = a, b, c do
        i.Size.Y = Vector2.new({a, b, c}, 0)
    end
    wait(.001)
end

wait(3)
sizeX(1, .1, -.01)
sizeY(1, .2, -.01)