I can embed graphics in an HTML report with an img having a src attribute = "data:image/png;base64,base64_encoded_characters_go_here"
.
It works fine in all the browsers I've tested.
The last hurdle, so far, is to embed the encoded favicon.ico file inside the HTML report so that the browser doesn't have to perform a GET.
So far, the best solution I have is one which requires the favicon to appear publicly on our web site. But that doesn't completely handle the self-contained goal we stated. This solution requires me to specify a "shortcut icon" link and if that truly is the only way to do, then so be it. But I'd like to know for sure. I just don't want to have a directory full of version-controlled favicon%d.ico files.
Background...
I have an XML => XSLT => HTML desktop application that produces HTML reports that can be self-contained and shared, say, via email attachments. The self-contained nature is useful for resolving a lot of version control problems that I don't want to solve. I have, in fact, solved most of them.
The goal, of course, in making self-contained reports is that the recipient's browser need perform no GETs. So, stylesheets and most graphics are embedded/encoded in the HTML page without significantly increasing the HTML report's size.
I say all this to head off a lot of obvious questions about why I even want to do this. But keep in mind, this is not a web site, it is simply a report generator.