Here’s a simple way to check the number of shutter releases (the real number of shots taken with a camera) for Nikon DSLR cameras (on other cameras or brands, I’m sure it’s really similar).
1. Take a photo with your camera or find the last photo stored in your computer (card, disk, whatever). The important thing to keep in mind is that it must be a photo taken with the camera without any external processing (NEF or RAW files, or untouched JPG’s). This information is stored in the EXIF data stored with the photo and it’s really easy to erase that information just by opening a JPG in Photoshop and saving it again.
2. Open the photo with Photoshop (I’ve used CS6, but it works in CS5, CS4, CS3 and probably CS2 will be alright too). If it’s a RAW file (NEF, RW2, DNG, etc), probably you’ll get the Camera RAW window first, so just hit Open Image on the bottom of the window to open it in Photoshop.
3. Go to File > File Info and you’ll have access to the photo’s metadata or EXIF information. The information is divided in tabs, so scroll to the ADVANCED tab and open the tree folder “Schema (http://ns.adobe.com/exif/1.0/aux/). The number of shots is stored in the aux:ImageNumber property.