I think I figured it out. Here's the possible situation:
The photos of N266M was first uploaded to N56LT by mistake (I can see Bluedharma posted a few photos of N56LT just before N266M), so these photos are now linked to aircraft record of N56LT.
Then tail number of these photos are corrected to the right one. But the program has a bug, it doesn't change associated aircraft record at the same, thus they still show up as N56LT, despite the tail number says N266M.
It will be fixed.
Ken