Could preview-latex store its temporary files somewhere else than in the current folder? See e.g. the following stackexchange threads
http://tex.stackexchange.com/questions/284459/auctex-preview-latex-temporary-files?noredirect=1&lq=1
I've tried fiddling with preview-create-subdirectory but I can't seem to make it work. Ideally, there'd be one defcustom preview-latex-temp-dir which defaults to ".", and which the user could set to something else, the same way backup-directory-alist works.
My use-case is that it produces a ton of small files, and dropbox really doesn't like that and clogs my computer (dropbox doesn't support ignoring files ala .gitignore, for whatever reason).
Best,
Antoine