He snapped a picture of me.他为我拍了张快照。

snap表示拍快照，当然表示拍照也可用take,上句相当于 He took a picture of me.

snap本指使发劈啪声，捻手指发劈啪声，之所以有snap a picture是因为按快门时照相机会发出类似的喀嚓声。