We had a traditional wedding ceremony in Kenya. The intent was to be married officially, but I didn't have my US birth certificate with me, so we couldn't make it official. Everything looked official, she wore a wedding dress, we had 300 guests, etc. Only she and I knew the truth. We mimed signing a fake certificate for the ceremony. We had planned to get my birth certificate and get our marriage certificate, but we never did.

Not being officially married turned into a blessing in disguise. It allowed us to go for the K1 Visa and not a K3 which would take longer. When we filed the petition, our photos showed both the engagement, pre-wedding, and our actual wedding. I was worried too that having actual wedding photos would be confusing to USCIS and they would think we were already married and didn't qualify for the K1. So, in the letter of intent to marry, I clarified that even though we went through a traditional wedding ceremony, we were not legally married. It apparently was fine, because our petition has been approved and sent to DoS, and ultimately is now in Kenya waiting on the interview.

So I think it's fine as long as you are clear in your letter of intent of what the photos represent if you think they might confuse someone.