Disabling underscore-to-subscript in Emacs Org-Mode export

In addition to the use of publishing by modifying your org-publish-project-alist variable as @user1248256 suggested, you can directly specify the org-export-publishing-directory variable within your file:

#+bind: org-export-publishing-directory "./exports"

* This is a test headline
Some text here.  This should be exported to the "./exports" directory.

Upon export it will be placed in the "exports" directory, but only if that directory exists. If it does not exist, you will get an error message in the console.

According to the documentation

or (info "(org) Previewing LaTeX fragments")

You can customize the variable `org-format-latex-options' to
influence some aspects of the preview. In particular, the `:scale'
(and for HTML export, `:html-scale') property can be used to
adjust the size of the preview images.

A quick C-hvorg-format-latex-optionsRET gives us:

org-format-latex-options is a variable defined in `org.el'.
Its value is (:foreground default :background default :scale 1.0 :html-foreground "Black" :html-background "Transparent" :html-scale 1.0 :matchers
             ("begin" "$1" "$" "$$" "\\(" "\\["))


Documentation:
Options for creating images from LaTeX fragments.
[snip]
:scale       a scaling factor for the size of the images, to get more pixels
[snip]

For example, to set the scale to 2.0:

(setq org-format-latex-options (plist-put org-format-latex-options :scale 2.0))