Help with Custom cards and sets.

So I have been at this for about 2 days now without being able to get anywhere. That being adding custom cards to forge with art. I have got them to show up in game and they even work as I script them, However I have added art with "name.full.jpg" and nothing seems to work. I'm not sure why but everything seems to be in working order and where things are meant to go but for one reason or another it just doesn't seem to want to show my art for the new cards.
Side note* I would also be super grateful if someone could tell me how to add custom sets to the game. All my card have ??? as there three letter set code.
Thank you in advance for anyone will to help up.
Side note* I would also be super grateful if someone could tell me how to add custom sets to the game. All my card have ??? as there three letter set code.
Thank you in advance for anyone will to help up.