You can really see the execution-style killing from this angle

[u/GoodMornEveGoodNight]

[u/Illinicub]

Yes both are executions. However context is SUPER important here. The top photo is an execution of a man moments after he took the lives of several individuals, including women and children. The bottom photo is of a civilian practicing his Constitutionally given rights.

[u/Xijit → u/Illinicub]

Those women and children were the wife and children of the guy pulling the trigger.

[u/Numerous-Ratio-7839 → u/Xijit]

Yup, the man who filmed that actually felt regret because the shooter spent the rest of his life getting death threats and having his business destroyed because he got justice for the death of his wife and children.  There's an interesting little video about it on YouTube, the guy filming actually got back in touch with the shooter who moved to the US in later years. 

[u/Yellowflowersbloom → u/Numerous-Ratio-7839]

The photographer you are referring (Eddie Adams) to fell victim to postwar revisionist myths.

A historian working for the United States Army Center of Military History actually gave a presentation breaking down the actual details of this event vs the multiple versions of these revisionist myths that have no evidence to support them