If you try to convert a web-page of wikitolearn in which there are some images uploaded there will be some nice and funny problems, as the fact you could find an image there would never be or the images there are will be moved 2-3 pages up or down in pdf file. An example:
See this web-page: http://it.wikitolearn.org/Analisi_I/Sommario_sullo_studio_di_funzione
Then try to download the pdf and look at where (and what) images are.