Compiling document with images for MultiMarkdown - images not being passed through

I am new to Scrivener and experimenting with inserting images for a technical book I am writing. I can compile this material to a Word document without any difficulty, but when I try to compile for MultiMarkdown only some of the images are passed through.

(I want to use MultiMarkdown because this seems to handle my equations and references very nicely.)
But I’m entirely puzzled why some of my images just don’t appear in the output file when I change the compiler!

Thanks for any help.