GoogleImageProxy

[wilderness]

No clue when Google changed their image UA.
I've had the former Googlebot-Image in robots.txt since at ;east 2006.
Over the years there has been a few erroneous full-site crawls.

66.102.6.201 - - [19/Aug/2020:13:13:36 -0700] "GET /MySub/MyIMage.gif HTTP/1.1" 403 435 "-" "Mozilla/5.0 (Windows NT 5.1; rv:11.0) Gecko Firefox/11.0 (via ggpht.com GoogleImageProxy)"

Overall grabbed less than a dozen images (403s).

[lucy24]

GoogleImageProxy has nothing to do with search functions.

It seems to come up every year or so:
2019: [webmasterworld.com...]
2018: [webmasterworld.com...]

:: detour to logs and headers ::

Poring over headers reveals that (a) thanks to having a couple of SetEnvIf directives in the wrong order, I’ve been blocking it all along in spite of intended hole-poking (the FF/11 element) and (b) it wouldn’t have made any difference, because there are header deficiencies that I could swear I’d also poked a hole for on other grounds. This will take more investigation, though I’m not absolutely certain it’s worth the bother.