Jodi, I'm so sorry for your loss. With time, it will get easier. It never fully goes away...but you will be able to look back on all his good times, and though it might hurt, you'll be able to smile a little more each day.
As for the pictures burned in your mind, even when you don't see it, it's always there...one of my dogs recently was killed by car in an awful accident...There were nice people who picked him up and took him to the vet, though it was too late...the vet described his condition when he came in, and I can picture the pain and suffering, and feel it in my heart...so, whenever those thoughts take over, I think of happier times with him...
And remember, you never let go of memories...