Why does the image become blank?

So I'm thinking of adding a card pack opening system and I've got everything working fine except changing the image anyone know what's wrong? It only becomes a blank image.

    local roll1 = math.random(1, 100)

    if roll1 <= 45 then
        card1.Image = "https://www.roblox.com/library/7220627763/Common"
    elseif roll1 > 45 and roll1 <= 80  then
        card1.Image = "https://www.roblox.com/library/7220628357/Rare"
    elseif roll1 > 80 and roll1 <= 99 then
        card1.Image = "https://www.roblox.com/library/7220629093/Epic"
    else roll1 = 100
        card1.Image = "https://www.roblox.com/library/7220629761/Legendary"
    end