My pictures go in a folder called 'camera' which is a subfolder of the 'DCIM' folder, which is in the sdcard. This is how it worked via stock ROM and now on ThudeROM, and it was how it worked on my Samsung Moment. I googled "picture location in Android" and all results indicated that pictures that users could not locate were always found on the sdcard. I don't know how the Nexus S (or Android 2.3 in general) will work (it does not have an sdcard - I'm assuming that part of the internal memory will be formatted so that it can be mounted on to a pc like a sdcard), but other than that, it appears that all Android phones put the pictures on the sdcard. In fact, as a test I unmounted my sdcard and opened the camera app. It would not let me take a picture until I inserted an sdcard. So I don't know exactly where on your sdcard your pictures are, but I'm pretty sure if they exist they are on your sdcard.