I recommend to ease the SGML-blocking behavior of the forums and adding MathML-Notations ( or (La)Tex Math partial support ) for all ( or the science ) forums. That would be a great way to serve equations at the forum without linking to external services or images.

What is MathML?

MathML is an XML-based mathematical markup language, that has been built with the intention to serve mathematical formulas embedded or standalone. MathML (as all other XML derivates) can be embedded into HTML5. It's supported in some major browsers, the number of browsers that require a MathML polyfill will decrease over the time.

What is LaTex / Tex Math?

LaTex Math is the LaTex notation for mathematical formulas. LaTex Math requires server side processing and should be something that might be converted into MathML. The transformation could be done along SnuggleTeX by the schools of physics and astrology of the university of Edinburgh. LaTex Math is also a bit easier to write than MathML and therefore easier for non-technical users.

SnuggleTex: http://www2.ph.ed.ac.uk/snuggletex/documentation/generating-content-mathml.html
MathML: https://en.wikipedia.org/wiki/MathML
LaTex Math: https://en.wikibooks.org/wiki/LaTeX/Mathematics