Areas of an HTML document are not displayed in a Vault generated rendition. Images are missing.
HTML coding is not in Standard Generalized Markup Language (SGML) syntax.
HTML loaded to Vault should be in standard SGML syntax in order to be properly parsed for display in the Vault generated rendition. Often this is due to the format of comments around code, which can cause some of the HTML to be skipped. Refer to the SGML Primer which discusses standard SGML syntax for comments.
SGML Primer Chapter 3 - FreeBSD Documentation Project Primer for New Contributors