group of Irish Free State Army soldiers firing artillery on the Four Courts

The photograph is probably by W.D. Hogan. One soldier is in the process of firing, the others stand at some distance mainly with their ears covered. (Similar photograph published in Michael Hopkinson's Green against Green (1988) with the following caption: ‘The opening shots of the Civil War, fired from Free State 18 pound field artillery supplied by the British Government. The gun was stationed at the junction of Bridge Street and Usher's Quay, just across the Liffey from the Four Courts'.