Forum Moderators: open
68.2.239.nnn - - [05/Jun/2016:22:54:44 -0700] "HEAD /ebooks/alcott/images/M-main552.png HTTP/1.1" 200 344 "-" "picTrove%202%20pro/177 CFNetwork/758.4.3 Darwin/15.5.0"
68.2.239.nnn - - [05/Jun/2016:22:54:48 -0700] "GET /ebooks/alcott/images/M-main552.png HTTP/1.1" 200 37163 "-" "picTrove%202%20pro/177 CFNetwork/758.4.3 Darwin/15.5.0"
68.2.239.nnn - - [05/Jun/2016:22:55:07 -0700] "HEAD /ebooks/alcott/images/M-main534.png HTTP/1.1" 200 344 "-" "picTrove%202%20pro/177 CFNetwork/758.4.3 Darwin/15.5.0"
68.2.239.nnn - - [05/Jun/2016:22:55:35 -0700] "HEAD /ebooks/alcott/images/M-main543.png HTTP/1.1" 200 344 "-" "picTrove%202%20pro/177 CFNetwork/758.4.3 Darwin/15.5.0"
The percents decode to "picTrove 2 pro"; the rest implies something to do with a mobile. Three HEAD, only one of which was followed-up by a GET.