I see pictures of a schizophrenic brain and an Alzheimer's brain, and they look the same to me.

I suppose the difference would be in the manifestation of symptoms.

Am I right?

difference in biochemistry, reasons. And, futhermore, Alzheimer's disease is a neurodegenerative one, whereas schizophrenia is due to other mechanisms.
It's a pity, you're talking here about similarity of these two diametrically opposite diseases. ahh

Doesn't mean we can't learn something about one disease from the other.
Alzheimer's is characterised by a pervasive cognitive decline, similar in some respects to that seen in a cognitive deficit sub type of schizophrenia (why do they both have such terrible memory problems?). Alzheimer's patients suffer from delusions, a core feature of schizophrenia. Both patients also suffer from apathy, agitated moods, lack of insight. There are quite a large number of differences between the two disorders, but there might be some commonality with some specific symptoms.