There is no direct support for formula editing. Saving images
with Wolfram is not a bad solution.
One reason we don't offer this is that whatever we put in will
never be as good as an app whose focus is formulas, like Wolfram
Alpha. So from our perspective, it actually works better to use
professional quality equation editing, just as you would want to
use professional quality drawing apps for illustrations.
Something we may add at some point is a simple drawing tool for
making images. Is that something you think you would use to write
equations, or would hand written equations not be of interest?