Pictures are stored but not displayed in Camera Roll

Well, I've been running low space for a long time and this led to a sudden disappearing of old photos (actually 5000 of them - the oldest ones) in camera roll. I don't know how how that worked - maybe iOS tried to free up some space by removing the thumbnails (without asking me???). The main advice is to remove the **photos.sqlite** and other similar files from **PhotoData** directory. That did nothing - the restored base is lacking my OLD ones. Still you can find them all in DCIM folder. How can I add them back to sqlite??? Thanks a lot!! upd. ios 9.1