Ultrasound picture coception date questions

[confusedguy]

Hello I hope I'm posting this in the right section and I hope someone might be able to help me.

I'll give you a little background first. My girlfriend and I have been in a long distance relationship for a while. We met for a holiday a few weeks ago. We spoke today on the phone and she informed me we are pregnant. I took the news well but I was a little surprised inside as I thought I had been pretty careful when we were together.

She sent me a picture of the ultrasound. I have never looked at one so I sent it to my mom and asked her if she could fill me in on what I'm looking at. She asked how far along my gf said she was and I told her and asked if I was sure as from the ultrasound she looked farther along.

After I spoke with my mom I started looking online for ultrasounds by week and sure enough all the photos I found looked like she was farther along than she had told me.

I'm not going to say what week she said she is in I would just like to see what you all think from the picture and after I get some feedback I'll post the rest of the details.

Thanks for your input in advance!
http://farm5.static.flickr.com/4075/...a299e75f_b.jpg