Hi,
Are you extracting images from DatabaseViewer? You can select if you want the timestamp or id as filename. If you choose the id, you can export poses in RGB-D SLAM format + ID so that you can know which pose corresponds to which image.
In database viewer, can you see the loop closures you added? In Graph View, can you see all poses? If you don't see all poses, maybe some have been ignored (even if images are saved) if RGBD/LinearUpdate is > 0 (default is 10 cm).
You can reprocess your database like this:
rtabmap-reprocess --RGBD/LinearUpdate 0 input.db output.db
and see if the number of poses and number of images now match.
PS: I am glad that my previous answers are helping the community, this is why I continue supporting this project (even if I am late sometimes because of some deadlines or consulting).
cheers,
Mathieu