It's a crimean war picture
Actually, if you look closely, you can see the enemy is Austrian Grenadiers. That picture is from the Second Italian War of Independence, which is yet another war under Napoleon III.
EDIT: I was considering making a SIWI mod before deciding on CW. I chose Crimea as all which was involved in SIWI was France, Sardinia, and Austria. A bit less interesting...
#inb4 Docm