Keeping a diary and pictures is probably a good idea. I hadn't really thought of it, but it might not help in my case. My AW won't admit to being drunk... even while she's drunk... much less a week later.
She'll admit that she drinks... no problem there... she just refuses to admit that she ever gets drunk, or that it's a problem.
The fact that your wife admits she has a problem could be a positive sign. I hope things work out for you.