Mansur al-Hallaj (858 -922 AD) was a Persian mystic, revolutionary writer and pious teacher of Sufism most famous for his poetry, accusation of heresy and for his execution at the orders of the Abbasid Caliph Al-Muqtadir after a long, drawn-out investigation.
(source, where you can read the full story)
The precise story about this picture is unknown, to me at least. I couldn’t find any reliable references. It’s assumed that this is an image of a public execution in China.
(source unknown, more on capital punishment in China is here)
“Pieta”, Jesus in the electric chair, by British artist Paul Fryer, in the private collection of François Pinault in France
Francisco Goya, The Shootings of May 3, 1808. Goya sought to commemorate Spanish resistance to Napoleon’s armies during the occupation of 1808 in the Peninsular War.
Cook County kept a gallows around until 1977 in case “Terrible Tommy” O’Connor, who escaped on the eve of his execution in 1921, was ever apprehended
More images of capital punishment are here, here, here, here, here, here, here and here. More on capital punishment in general here. Some data are here. And other collections of human rights images are here.