X-100 and X-E1 same file name
Right after you load new firmware onto the X100, it doesn't know what number to start using for the next photo. Some people either deliberately or accidentally stick an SD card into the camera with the last image they took, so the camera sees that and uses that number to start numbering from. You can exploit this behavior to set the number to anything you want by just renaming an image using the file system on your computer and then putting that image file onto the card and into the camera. This is what I did when I started getting conflicts with images from an older Fuji camera.