I've been using Pandoc for documents where I have mostly text and images. It's also worth to note that LaTeX commands can be written in the Markdown document and most of the time it'll work correctly. Additionally, for custom preamble additions you can create a separate file and pass it to pandoc with -H.
Here is a document I created recently using pandoc, python, inkscape and bmake, where I put a bit of LaTeX in the markdown document:
You might notice some untransformed LaTeX commands in the figures. That's no fault of pandoc mind you, since the figures are just graphic files to be included from the POV of pandoc, that's just because I haven't bothered yet to get that part right due to there being no real gain for me at the moment from getting that part right so I just type LaTeX in the figure text also even though I do not transform those.
Pandoc is a document converter. I can make a Markdown file and output to LaTex or just PDF. http://pandoc.org/
I have learned that I get things done faster and works 90% of the time for my needs.