Hi! My husband and I sent in our application about four months after our wedding. We were in a relationship for six years prior to that, though. We chose a bunch of photos from each year, which probably showed our "evolution", if you may. I think my husband chose photos pretty well. There were ones with us on dates, on lunches with family, on trips and vacations. He even included our graduation photos together. I can try to give you some tips if you want to have more "photographic" proof for your app. Here goes...
I suggest gathering photos of you two with different groups of people: your families, friends, in different events and such. I don't think it has to be a lot, I recall a member sent in their app with something like a handful or so of photos (I cannot remember who this was, when it was, or which VO they sent it to so please be a bit wary of this!) If you have dinner with friends or family, try to take a photo. You two are out on a date or a day trip somewhere? Snap some pictures. Before you know it you have a lot of photos to choose from.
I agree with mikeymyke, the ceremony doesn't have to be huge. Have family, maybe good friends, and have a simple party afterwards. Also, zardoz has a great point. Living together, I think , would be another point in your favor. You will also have a lease, joint bank accounts and bills and such that I think you can also submit.
Okay I think my reply has gotten out of hand. Don't stress about it too much! Have fun with your girlfriend, live life, and love each other. Your application time (and the stress that comes with it, lol) will come. I wish you and your girl the best of luck, and happiness together
