Very cool postcards.
The high jumper is not a flop style. Even when he did it, there was some question whether Fosbury was within the rules. Diving over the bar was forbidden, and what he did was essentially diving over just upside down.
The jumper is finishing a straddle style jump. The jumper basically jumps, kicks one foot over, then in mid jump is looking down at the bar while parallel to it. the final bit is to kick the other leg up and over. Just like Fosburys flop, if it's done right the jumpers center of mass actually goes under the bar since his legs and arms are under when his body is over.
That final kick often flips the jumper over.
Nice example here
https://www.youtube.com/watch?v=w_CpP_NSlmc
The line on the other side of the bar and the guy with the rake for the loose dirt landing area are also clues.
Dad coached HS track, including high jump and pole vault. When we were doing it in gym in HS he tried teaching me both the flop and straddle. (He as asst superintendent by then and not coaching so we tried it at home) I had no jumping ability, and never cold get the hang of either style. My best was painfully low, under 4ft and often barely better than I could do just standing there.
Steve B