I took a belly picture at 10 weeks. But I'm not going to show it until I can put it side by side with a pic taken at 16-18 weeks. Why? Oh, well, because I've never seen an early belly pic of someone who's starting out as fat as me. My belly size currently has nothing to do with the twins swimming around in there and everything to do with my fondness for chocolate and hatred for exercise.
I have my belly pic taking uniform set aside so I can always wear the same thing for direct comparisons. I only took a pic at 10 weeks so that if I get deep into the second trimester, I'll have something for reference to see if my shape is changing or if I'm still just the same kind of fat.