Those are dead bodies. They were beheaded (which lasts seconds and is one of the most painless methods of execution unlike being hung by a crane which can take minutes as 1000's of videos from Iran confirm) and afterwards their bodies were put at display for a certain amount of time (a few hours). This is the most severe punishment in KSA.
This was a gang of robbers and murderers who terrorized a community in Jizan for over 1 year. A local judge suggested this punishment and in their case this was well deserved.
Anyway I have nothing against executions. However beheading is no doubt more human than using cranes and besides you were the one that started talking about beheading.
Iran:
Speaking about executions, KSA executes less people per capita than Iran.
Anyway I have witnessed an execution in person so I am not afraid of executions, lol.
May I inform you of the fact that your former idols (France) especially during the Shah, essentially used beheading (guillotine) until 1979. They did that for a reason.
1) it's relatively humane, painless and quick as far as executions go
2) it's cheap
3) it gives a strong and graphic message to potential criminals
4) its Islamic in the sense that this has been the preferred execution method in the Muslim world historically
5) Beheading used to be reserved for people of a noble background. In Europe as well. Peasants were hanged usually while nobility/kings had the "honor" of being beheaded by a sword or axe. True story.