How do I get a player's image onto a part using a GUI?

I'm trying to make a fallen screen from the hunger games, but whenever I try to use it nothing happens. (Filtering Enabled)

local clicker = script.Parent.ClickDetector

local fallen = workspace.Fallen
local screen = workspace.FallenScreen
local fallenimage = workspace.FallenScreen.Decal

local gui = game.StarterGui.ScreenGui
local username = gui.User

local guiclicker = gui.Confirm

username.MouseButton1Click:Connect(function()
fallenimage = "http://www.roblox.com/Thumbs/Avatar.ashx?x=100&y=100&Format=Png&username="..username
end

Thanks if you can help.

Day late, but basically you need to define the Local Player, as greatneil80 mentioned in his comment.

This could easily be done by changing username to something like username = Players.LocalPlayer.Username which will work locally, because it is for a script on a GUI, which should be a local script.

This should be able to pull the image you desire, and work locally without any issues.

It's just not possible. I wish it were D:.