[The authenticity of the photo has been challenged, but I know a woman with a relative who can verify that it was not staged. Though it might take some time, I can contact her for details. The fact remains that many priests were murdered during this period of Mexican history, known as the Cristero War 1926-1929. Graham Greene wrote a novel about it, The Power and the Glory. He was a newspaper correspondent in various places and spent some time in Mexico.]
Below is a picture of Father Miguel Pro, SJ, executed by firing squad on Nov 23, 1927, in Mexico City. I obtained the picture from Wikipedia [in the public domain].