I have tried rbxassetid://, http://www.roblox.com/asset?id=, and others, and it won't load my images, even with preloading, waiting, etc. Here's my scripts.

Local

local ProductList = require(script.ProductList)
wait(.25)
for i,v in pairs(ProductList.Products) do
	game:GetService("ContentProvider"):Preload(v.IMAGE)
	print("preloaded " .. v.IMAGE)
end

for i,v in pairs(ProductList.Products) do
	wait(.1)
	local Clone = script.Template:Clone()
	Clone.Name = v.NAME
	Clone.Title.Text = v.NAME
	Clone.Dropdown.Description.Text = v.DESCRIPTION
	Clone.Dropdown.Price.Text = v.PRICE
	Clone.Dropdown.PlaceID.Value = v.PLACEID
	
	Clone.Parent = script.Parent
	Clone.Dropdown.ImageAssetThing.Image = v.IMAGE
	print(v.IMAGE)
end

Module

return {
	Products = {
		["Product"] = {
			["NAME"] = "Cafe", -- Product Name
			["PLACEID"] = "6304254721", -- Game ID to teleport to when they click "TEST"
			["DESCRIPTION"] = "High-Quality Cafe + Mop System + Realistic Jetski with great physics. Comes in packages. Check Discord for more.", -- Product Description
			["PRICE"] = "3k-4k", -- Product Price
			["IMAGE"] = "http://www.roblox.com/asset/?id=391827916", -- Product Image
		},
		["Product2"] = {
			["NAME"] = "CafeV2", -- Product Name
			["PLACEID"] = "6304337305", -- Game ID to teleport to when they click "TEST"
			["DESCRIPTION"] = "High-Quality CafeV2 + Mop System + Jetski + Food System. Comes in packages. Check Discord for more information.", -- Product Description
			["PRICE"] = "3.5k-5k", -- Product Price
			["IMAGE"] = "http://www.roblox.com/asset/?id=391827916", -- Product Image
		},
		["Product3"] = {
			["NAME"] = "Training Center", -- Product Name
			["PLACEID"] = "6304295617", -- Game ID to teleport to when they click "TEST"
			["DESCRIPTION"] = "High-Quality Training Center. Comes with View Stage GUI. Check Discord for more information.", -- Product Description
			["PRICE"] = "3,500", -- Product Price
			["IMAGE"] = "http://www.roblox.com/asset/?id=391827916", -- Product Image
		},
		["Product4"] = {
			["NAME"] = "Event Center", -- Product Name
			["PLACEID"] = "6304291250", -- Game ID to teleport to when they click "TEST"
			["DESCRIPTION"] = "High-Quality Event Center. Comes with View Stage GUI. Check Discord for more information.", -- Product Description
			["PRICE"] = "3,000", -- Product Price
			["IMAGE"] = "http://www.roblox.com/asset/?id=391827916", -- Product Image
		},
		["Product5"] = {
			["NAME"] = "Staff Management Reforms Center", -- Product Name
			["PLACEID"] = "6304337048", -- Game ID to teleport to when they click "TEST"
			["DESCRIPTION"] = "High-Quality Staff Management Reforms Center. Comes with View Stage GUI. Check Discord for more information.", -- Product Description
			["PRICE"] = "3,500", -- Product Price
			["IMAGE"] = "http://www.roblox.com/asset/?id=391827916", -- Product Image
		},
		["Product6"] = {
			["NAME"] = "Scripted Food Pack", -- Product Name
			["PLACEID"] = "6304306171", -- Game ID to teleport to when they click "TEST"
			["DESCRIPTION"] = "High-Quality Scripted Food pack, able to click to get things. Comes with menu. Check Discord for more information.", -- Product Description
			["PRICE"] = "2,500", -- Product Price
			["IMAGE"] = "http://www.roblox.com/asset/?id=391827916", -- Product Image
		},
		["Product7"] = {
			["NAME"] = "Homestore", -- Product Name
			["PLACEID"] = "6304305094", -- Game ID to teleport to when they click "TEST"
			["DESCRIPTION"] = "High-Quality Homestore. Comes in packages. Check Discord for more information.", -- Product Description
			["PRICE"] = "2k-3k", -- Product Price
			["IMAGE"] = "http://www.roblox.com/asset/?id=391827916", -- Product Image
		},
		["Product8"] = {
			["NAME"] = "Hotel", -- Product Name
			["PLACEID"] = "6304306488", -- Game ID to teleport to when they click "TEST"
			["DESCRIPTION"] = "High-Quality Hotel with packages. Check Discord for more information.", -- Product Description
			["PRICE"] = "3.8k-5k", -- Product Price
			["IMAGE"] = "http://www.roblox.com/asset/?id=391827916", -- Product Image
		},
		["Product9"] = {
			["NAME"] = "London Heathrow Airport", -- Product Name
			["PLACEID"] = "6304337429", -- Game ID to teleport to when they click "TEST"
			["DESCRIPTION"] = "Airport based on London Heathrow Airport. Comes with scripts. Check Discord for more information.", -- Product Description
			["PRICE"] = "4,500", -- Product Price
			["IMAGE"] = "http://www.roblox.com/asset/?id=391827916", -- Product Image
		},
		["Product10"] = {
			["NAME"] = "Interview Center", -- Product Name
			["PLACEID"] = "6304309144", -- Game ID to teleport to when they click "TEST"
			["DESCRIPTION"] = "High-Quality Interview Center. Comes in packages. Check Discord for more information.", -- Product Description
			["PRICE"] = "2k-3.5k", -- Product Price
			["IMAGE"] = "http://www.roblox.com/asset/?id=391827916", -- Product Image
		},
	},
	
}
Anonymous