Michael, I have three large volumes of a series of five titled "The Image of War: 1861-1865". They are adult "picture books" and I highly recommend them. However, you will find the vast majority of photos are Union soldiers, ships, batteries, etc. To my knowledge, there is no large source of photos of Confederate soldiers. I can only speculate why the photographers did not photograph them more.
There are many photos of dead Confederates, but I have rarely seen dead Yankees. My theory is these photographers must have been Yankees and either they chose not to photograph dead Union soldiers are they were censored and threatened with imprisonment by the Lincoln regime.