When saving images on one device, they are not automatically transferred between devices.
Thus when exporting data or syncing between devices you may find exclamation marks where an image should be.
This means that the image has not been copied over to the new device yet.
The following is the procedure for doing so:
1) Plug in the device which contains the images in Car Logbook into your computer and open iTunes
2) Click on your device on the pane in the left under the "Devices" section
3) Click on apps, and scroll down to the "File Sharing" section
4) Select Car Logbook, and select all image files you wish to copy
5) Click "Save to", and save to a place on your computer
6) Now plug in your second device, and repeat steps 2 and 3
7) Click "Add..." and select the files which you saved on your computer