I believe the following code should send an image inside the embed. It’s up to you if you want to keep the author part or change it to the embed title/description.
local http = game:GetService("HttpService")
game.ReplicatedStorage.Remotes.Upload.OnServerEvent:Connect(function(plr)
local data = {
["embeds"] = {{
["author"] = {
["name"] = "Ad here!",
["icon_url"] = "https://t1.rbxcdn.com/a6042d6b9a37a5e88b7636e31046c25e",
},
["image"] = {
["url"] = "https://t1.rbxcdn.com/a6042d6b9a37a5e88b7636e31046c25e",
},
}}
}
local encodedData = http:JSONEncode(data)
http:PostAsync("webhook", encodedData)
end)