In Volume 1 .p.22-23 of Miller's "Photographic History of the Civil War" is photograph of Battery D of the 2nd US Artillery. Allegedly a caption claims the battery is about to fire at the enemy near "Mansfield house".
Likewise there is a photograph of 1st Connecticut Battery near Fredericksburg May 2, 1863 -also about to fire on the foe? Were these pictures taken in battle?