If you have a working LaTeX installation and dvipng, dvisvgm or convert installed1, LaTeX fragments can be processed to produce images of the typeset expressions to be used for inclusion while exporting to HTML (see see LaTeX fragments), or for inline previewing within Org mode.
You can customize the variables
org-format-latex-header to influence some aspects of the preview. In
:scale (and for HTML export,
property of the former can be used to adjust the size of the preview images.
You can turn on the previewing of all LaTeX fragments in a file with
To disable it, simply use