Pictures are good. But they are not the only proofs you'll need. You can include proof of your travel there... The stamps on your passport. And if you took some trips together while in Ghana include proofs that have both of your name. One thing I would suggest is since you are in the US right now, you can wait 1-2 months before sending your petition so that you can create more proofs...
Such as:
Emails, chats (skype, whatsapp, etc), phone calls, mail, and anything else you can think of that will help prove your case.
While it may seem waiting is too long, making sure that you send a complete package is better than sending something that may require an RFE or get denied... Good luck!
Tiff&Babs reacted to mtcmk1 in Are Pictures Enough ?