The highest photograph ever captured by humans from Earth orbit: Sun glare over Australia from 740 nautical miles, 12-15 September 1966

Vintage chromogenic print on fiber-based paper, printed 1966, numbered "NASA S-66-54706" (NASA MSC) in red in top margin, with NASA caption and "A KODAK PAPER" watermark on verso, 20,3 x 25,4 cm

“The Sun was slowly settling into the west, causing an angular reflection in the glass window of the spacecraft. Dick Gordon and I were looking at western Australia. This picture was taken approximately when we reached the high point of our high altitude orbit. This was the view from 739.4 miles. We were excited and although we had planned the high orbit for months, we never realized what a sight we would see. Fifty minutes earlier we had ignited our Agena rocket engine for the longest burn ever made to change an orbit.”
Pete Conrad (Cortright, p. 195)

From the mission transcript when the photograph was taken:
041:04:36 Conrad: I’ll tell you, you can’t believe it!
041:04:42 Conrad: Just out of my left window I can see all the way from - -
041:04:47 Conrad: - - the end, around the top of the world all the way around about 150
degrees, including the horizon all the way around.

Literature:
LIFE, 30 September 1966, ppg. 104-105; Exploring Space with a Camera (NASA SP-168), Cortright, ed., pg. 195