I have relevant photos of "special" flights / aircraft / people in my logbooks as discussed above.
As someone who does his fair share of interviews, I find it rare among the younger pilots to do so (maybe they don't think first solo is relevant, but I certainly recall Ngaire Moxley of RQAC sending me on mine in C152 VH-HCC...), but reasonably common amongst older pilots (maybe we appreciate these things more with time?).
When I see such photos in a logbook , often I use it as a discussion point to get the candidate to open up and speak about a topic comfortable to them. I certainly don't view it negatively, but having said that, a pic on every page would be excessive!
By way of example of how inportant this really is from a career history perspective, I have the honour of possessing my uncle's logbook from WW2 - during which he flew Hampdens in operations over Germany (some nights over 8 hrs logged...) and in the hunt for the German battleship "Tirpitz" - there are no photos, but the notes in the book tell a tale (he even glued in his course reports - apparently he needed more work on rudder use and bombing skills were "average"!). Unfortunately, with the princely total of just under 400 hrs, his last entry contains a tail number, crew detail and no flight time - his FLTCOMD has endorsed the entry as "Aircraft failed to return". The book tells a tale that the man was never able to...