Can a photo of a page of a copyrighted book be used commercially or released into the public domain for reuse?
Generally, no. This is just reproduction and the copyright holder of the original work would retain copyright in the reproduction. In fact, if your photograph itself has little additional creativity and just reproduces the page, you might not have copyright in it yourself. This same situation applies to other creative works which may be under copyright, like paintings and sculptures.
Now, depending on other factors, you may be able to mount a fair use / fair dealing defense. One factor might be the portion of the work: if your page is an entire short story, or even the part with a key element of a factual report, that's pretty weak, while a random sample page might be considered okay — there's a point where the usage is "de minimis", which basically means "too small to matter". It's kind of surprising and counter-intuitive how small that has often been in court cases, though. You might want to consider how Google Books presents scans of works they don't have permission to show — they only show a few lines, not the whole page. Maybe they're erring on the side of caution — but maybe not.
But that's really out of scope for this site. The key thing is that a camera is not a magical device which wipes clean the creative slate.