Never saw this issue. Can you list your picture directory contents.
For internal memory:
ls -l /home/user/MyDocs/DCIM/
Does it shows the multiple items.
If not, what happens after resetting tracker-database (as user in xterm):
tracker-processes --hard-reset
It may take a while to for tracker to re-index all items.
(tracker is responsible for indexing media content on the phone)
its clocked n900 running latest stable CSSU...
any ideas?