Why wont my ImageLabel Scale from script?

My Image Label gets bigger/ smaller depending on its value inbetween two numbers and the script I use works on Frames but not image labels?

local PositionX = script.Parent.Position.X.Offset
local initX = script.Parent.ImageRectOffset
while true do 
wait()
local Mana = script.Parent.Parent.Parent.Parent.Parent.Parent.Parent.bin.Mana.Value
local ManaMax = script.Parent.Parent.Parent.Parent.Parent.Parent.Parent.bin.Level.Value * 175
local Pie = (Mana / ManaMax) --Missed Scale 
--script.Parent.Size = UDim2.new( 0, initX*Pie, 0, 30) 
script.Parent:TweenSize(UDim2.new(0, initX*Pie, 0, 30),"Out","Sine",0.25)
end