US embassy checks for validity of marriage. So u need to provide photos for the weeding. How many people are present. Court marriage only I would say would be a NO NO. If you are really so desperate you really need to have an actual marriage for your gf with your friend. Video tape to provide authenticity. I don;t know it photoshop would do for you or no. They really ask you about photos and then who the people are in the photos. US embassy doesn;t really accepts only court marriage papers for authenticity of your gf/friend's marriage. They require further evidence like wedding photos, wedding videos, wedding invitation card, wedding party palace photos bill etc. If you can really produce all these things you can surely go for it but don;t assume only marriage paper would do any good for you.
Regards,