You can surely include pictures or screenshots of your app. I have pics in mine. I have 1 main page like a TOC called userguide.html then have a userguide directory and put the remaining html files and pics in it.
K. Tsang CEng MBCS PMP PMI-ACP OCPJEA OCPJP
I found some pretty shells, some sea glass and this lovely tiny ad:
Devious Experiments for a Truly Passive Greenhouse!