Apple designed the iPhone, iPad and iPod touch Camera Roll to only contain photos and videos you take with the device. The same is true for the predefined Favourites, Panoramas, Selfies, Screenshots and Videos albums.
This is why it is not possible to add photos or videos from elsewhere to the Camera Roll or to any of these predefined photo albums.
To add photos, create a new album
To create a new album with CopyTrans Photo, click on the green photos symbol on the top left of the main program window. Please note that photos added to an album will also appear in the Photo Library. The Photo Library contains all photos and videos added to your device.
This is why you can’t add photos to the Camera Roll but you can easily do so by creating a new album with CopyTrans Photo.