Why doesn't an ImageLabel render an image?

So basically I'm trying to use one of Nasa's APIs to create a roblox game. The API obviously returns JSON and images get returned as URLs.

Here's my code, to test the API (Not the final code)

local HttpService = game:GetService("HttpService")

local URL = "https://api.nasa.gov/planetary/apod?api_key=my api key" -- Not giving out my API key

local response = HttpService:GetAsync(URL)

local data = HttpService:JSONDecode(response)

local screenGUI = game:GetService("StarterGui"):WaitForChild("APIData")
local imgLabel = screenGUI.Image

print(data["url"])
imgLabel.Image = data["url"]

The code gets executed fine with no errors or warnings, the ImageLabel shows a white square when rendering this image , even though it's Image property was changed. Why does this happen?

If it is a local script, do this:

local HttpService = game:GetService("HttpService")
local URL = "https://api.nasa.gov/planetary/apod?api_key=my api key"
local response = HttpService:GetAsync(URL)
local data = HttpService:JSONDecode(response)
local screenGUI = game.Players.LocalPlayer.PlayerGui:WaitForChild("APIData")
local imgLabel = screenGUI.Image

print(data["url"])
imgLabel.Image = data["url"]

if it is a server script, you can add a RemoteEvent in ReplicatedStorage then do this:

local HttpService = game:GetService("HttpService")
local URL = "https://api.nasa.gov/planetary/apod?api_key=my api key"
local response = HttpService:GetAsync(URL)
local data = HttpService:JSONDecode(response)

game.Players.PlayerAdded:Connect(function(player)
	local image = data["url"]
	game.ReplicatedStorage.RemoteEvent:FireClient(player,image)
end)

and then a local script in StarterPlayerScripts that has this:

game.ReplicatedStorage.RemoteEvent.OnClientEvent:Connect(function(image)
	local screenGUI = game.Players.LocalPlayer.PlayerGui:WaitForChild("APIData")
	local imgLabel = screenGUI.Image

	print(image)
	imgLabel.Image = image
end)